Mexico - II by Richard Travis

Plants of Northeastern Mexico with ornamental potential for South Texas

Part II Table of Contents The Braheas of Northeastern Mexico The Nolinaceae of NE Mexico Dasylirion, Nolina, and related genera Ornamental Yuccas & Hesperaloes from NE Mexico The Hechtias of Northeastern Mexico Some ornamental trees from the Tamaulipan thorn scrub

Vol. 8, No. 2

The Braheas of Northeastern Mexico It could probably best be summed up that there are two kinds of braheas in NE Mexico - Brahea moorei and everything else. Thatâ&#x20AC;&#x2122;s about the best I can do for this tricky group of plants, the most Mexican genus of palms. The genus Brahea has unfortunately received less attention than many palms, and really I canâ&#x20AC;&#x2122;t write anything much beyond a rough description of the different forms I know to exist in NE Mexico. All of the braheas (again with the important exception of B. moorei) in NE Mexico are closely related to, if not a part of, the B. dulcis complex, even though at least one has proven distinct enough to warrant segregation as a different species. Currently B. decumbens and - depending on whom you listen to - B. berlandieri are the only such recognized species. If you consider Brahea dulcis as a single species in the most generous sense, it is an impressively variable and plastic species which occurs throughout much of Mexico, forming this huge complex with many forms. In Gentes Herbarum, Bailey split many of the B. dulcis apart; among these would be B. bella of Coahuila and B. berlandieri from Nuevo Leon. Most of these have since been lumped back into one or two species. Virtually all of what is found in the drier regions of NE Mexico would comfortably fit into what Bailey described as B. berlandieri , including the green B. bella, though some of the low clumping forms seem to transition into plants which more closely match B. dulcis to the south. Brahea decumbens, while closely related to B. dulcis/berlandieri , appears distinct enough to be considered its own species by just about everyone. Some debate revolves around whether the northern forms of the vast B. dulcis complex should be included with dulcis or kept separate as berlandieri. Dr. Henderson in his Palms of the Americas lumps them together, but Dr. Hermilo Quero of UNAM and an authority on Mexican palms, has kept them separate. Bailey of course split B. dulcis up much more, and before that B. berlandieri had been assigned the name B. dulcis var montereyensis, which may perhaps turn out to be an appropriate name for this plant. Dr. Quero wrote his dissertation on the palms of Mexico and, while for now keeping B. berlandieri separate, spoke with me about the status of the genus this past summer (2003). He is currently working on these plants and right now appears to keep the two distinct, though he is not sure what to do with some plants which appear to have transitional characteristics. Some may even be distinct enough, he says, to belong to a new species. But until his work is complete and debated the braheas in eastern Mexico are still up in the air. As someone said, plants donâ&#x20AC;&#x2122;t grow in the wild with labels on them, and many plants in the Mexican flora are particularly difficult, whether it be the braheas or agaves or hechtias or you-name-it.

The differences between B. berlandieri and dulcis are distinct enough in their “typical” forms at the edge of their range, but again there is this lack of uniformity in many of the plants. It is especially challenging for us amateurs who are not able to perform extensive testing on these plants which is so critical to draw any substantive conclusions. In their ideal forms, these are the major differences between B. dulcis and berlandieri :

B dulcis - usually green leaves, often low-trunked, clumping or branching, long graceful curved inflorescences with the rachillae more than 5 cm in length. The inflorescences easily exceed the length of the leaf crown. Native to Southern Mexico. B berlandieri - leaves often with glaucous, at least on the underside, or green, single trunked, with a stiffer less graceful inflorescence with the rachillae less than 5cm long. The inflorescences do not generally exceed the length of the crown. From Northeastern Mexico. So most of the braheas in Nuevo Leon and Coahuila comfortably fit into the B. berlandieri category, and the braheas south of San Luis Potosi are closer to dulcis. Sounds easy enough to separate the two, right? Wrong. There are just too many intermediate forms found in between the two, if Tamaulipas didn’t exist it probably would be easy to keep the two separate. So I’ve decided here that the best thing to do is not try to pretend I know the difference between these plants but rather give you a rundown of what I and others have observed about the braheas from this part of Mexico. While that sounds a bit like an easy way out, there are some general trends that hold among the braheas of the region which are certainly worth noting. The differences are not so great from a floristic perspective as they are from a morphological and ecological viewpoint. It can also be comfortably stated, from cultivation at Peckerwood and elsewhere, that these differences are indeed genetic as they maintain these distinctions even when grown under the same conditions from seed. In the very broadest sense, it can be generalized that there are two basic forms of the dulcis/berlandieri type in NE Mexico: a single trunked taller form that occurs in hotter drier localities, and the lower clumping forms which occur in more mesic humid environs. Getting more specific, here is a more detailed description of the braheas known to occur in the region from northern Coahuila to San Luis Potosi. Starting from the north:

Brahea berlandieri ‘ La Babia’ (B. bella) - the name Brahea bella was used by Bailey to describe the single-trunked, green braheas that occurred about an hour’s drive northwest of Muzquiz at Rancho San Geronimo near the Rio La Babia, and again farther north towards Big Bend National Park. Bailey distinguished it from B. berlandieri by the completely green habit of the leaves, a minor difference in the fruit and the nearly spineless petioles. None of these distinctions has proven sufficient to maintain it as a separate species, though most growers prefer to use the old name, if for no other reason than using it as a way of distinguishing it from the other braheas of Mexico (and the name sounds nice too I suppose). In any case, it is the closest brahea to Texas and is the northernmost palm known from northeastern Mexico, growing up to around the 28th parallel. It is a handsome palm, with uniformly green lax leaves. Its occurrence in what is otherwise desert vegetation gives the places where it grows an oasislike appearance, where they grow out in the full hot desert sun of northern Coahuila. I had the good fortune of visiting the population at San Geronimo in May 1990, when Lynn Lowery went to collect seeds and photograph the plants. Driving north out of Muzquiz there is no indication at all that there would be any palms at all in this desolate region, the most interesting plants are a few Bauhinia lunaroides in some low hills and Quercus mohriana between Piedras Negras and Salinas. But all of a sudden the palms appear by the thousands, everywhere - on the hills, in the valleys, you can’t believe it. They disappear almost as quickly as they appear if you continue northwards. Lynn had been to this ranch at least once before our trip and was impressed with the palms, he had even begun to grow them at Anderson Landscape Nursery in Houston during the 1990s. Several people have grown plants from these collection trips, including Jennifer Staub in Austin. Carl Schoenfeld has subsequently collected it and occasionally offers it for sale. It does not seem to be a fast growing palm but it is, not surprisingly, pretty hardy to cold, and can grow outdoors in Central Texas is protected from severe cold when very small. Lynn had also collected a brahea in the region around Bustamante, between Monterrey and Nuevo Laredo. These plants appear to be different than what was called “true” bella - Mike Anderson told me that both green and grey forms are found there, which is not the case with B. bella.

Brahea berlandieri (B. bella) Above - NW of Muzquiz (Coahuila) Left - cultivated at Peckerwood Gardens

Brahea berlandieri (Nuevo Leon) - around Monterrey on drier mountainsides can be seen what appear to be tiny palms way on the mountaintops growing in what appear to be impossibly difficult places. Bailey called these palms B. berlandieri in Gentes Herbarum. One obvious difference between it and B. bella is that B. berlandieri can sometimes have silvery leaves, especially on the underside of the leaf. Apart from this and the other slight differences previously mentioned it is virtually identical to B. bella, and it grows in the same generally hot dry mountainous conditions, often on dry ridgetops or on the sides of impossibly steep cliffs. Bailey noted in Gentes Herbarum that there were two forms reported from the mountains behind Monterrey but he had no firsthand knowledge of them. Besides the population at Bustamante, there are reportedly braheas in a number of the smaller mountain ranges to the north of Monterrey, and these would undoubtedly belong with the same species/ subspecies considered as B. berlandieri. So too, surely, would be the single trunked arborescent braheas in southern Nuevo Leon and down towards the drier areas of the Sierra Madre in Tamaulipas, around Jaumave towards Palmillas. There does seem to be, however, a general increase in the frequency of “blue” colored braheas as you head farther south. I noticed a particularly nice one near Villa Maneiro back in the mountains, and have seen other notably glaucous specimens in SW Tamaulipas. At a very southern site, near Jalpan in Queretaro, Carl and Wade have reported a population of B. berlandieri where nearly all the plants have silver leaves.

Brahea berlandieri ‘Dr. Arroyo’ - this is an interesting variant on B. berlandieri. The most significant aspect of this palm is that all the plants in this region have short trunks, generally 6-8 feet tall at the most. What causes this dwarfness is perplexing. I have only seen them once, growing in a magnificent Dasylirion quandrangulatum forest, though I’ve heard reports of other short-trunked braheas in the general vicinity. Dr. Quero first pointed me to this interesting population. The region is neardesert about a mile above sea level, where we found them growing in full sun on the dry slopes of small canyons. All the palms we saw near Dr. Arroyo had green leaves. A population north of there in the mountains, however, had a number of plants with silver leaves, as well as a few taller plants.

Blue forms in Brahea berlandieri Above - south of La Escondida, NL Right - large tree north of Palmillas

Brahea berlandieri, a short form near Dr. Arroyo

Brahea ‘Silverback’ -this is a nice but rather tricky palm to describe. Carl Schoenfeld should probably be given credit for calling attention to this most interesting plant. It is found in the mountains around the Nuevo Leon/Tamaulipas border, extending as far north as the Villa Maneiro area. I first went to look for this palm in February 2003 without luck (made a wrong turn in the mountains) but did find it later that summer. It strikes me as closer to the many of the braheas found above Cd. Victoria more than anything else, though they seem to be more uniform and tend to have softer, more graceful lax leaves. The amount of glaucousness on their underside is, however, slightly variable from plant to plant. They appear to basically be a clumping form of B. berlandieri but are pretty distinct from the singletrunked trees known elsewhere in the region (there are, in fact, a few single-trunked forms of B. berlandieri just a few miles away in a different canyon west of Maneiro, and the two appear quite distinct). I found them growing in mostly full sun at approximately 2000’ above sea level, on slopes of soft limestone rocks mixed with loose soil. A fair number of the braheas above Cd. Victoria could comfortably fit this general description, though the variability in the palms seen above Cd. Victoria is considerably higher.

Brahea ‘Ciudad Victoria’ - no doubt these palms have added to the confusion of the braheas in the region. The braheas on the mountain pass west of Victoria are frankly a big mess and exhibit a higher degree of variability than other populations of braheas anywhere else I’ve seen in NE Mexico. The best guess I can give is that these plants represent some sort of intergrade zone or hybrid swarm. While the general trend in the braheas from north to south is from tall and single trunked to low and clumping, here almost every growth habit and coloration can be found. Some of the nicest palms here are as powdery blue as can be, while others are completely green. A few are as low as the forms seen near Tula and may show a tendency towards a shrubby, highly clumping habit. Others have a well developed central trunk with few (or rarely no) offsets. Most seem to fall in the middle, being mildly glaucous and having a short trunk with some suckers, not unlike Brahea ‘Silverback’ but more unstable. It seems therefore not unreasonable to think that there are really several forms of the B. dulcis/berlandieri complex present on the mountain, and that most of the material up there has backcrossed or intergraded to some degree. They are found growing in many situations, from full sun to the considerable shade of oaks, in generally rocky areas. One interesting phenomenon is that, as a general trend, the higher up the mountain road you go (which means the wetter it gets), the lower growing the braheas tend to be. They are most abundant along the crest in the oak forest, where they tend to be the smallest. Once you start descending on the drier backside of the mountain the height of the plants quickly picks up again. A phenomenon not lost on me is that at the crest of the road, where the braheas are the most abundant, is the main place along the road where the very distinct B. moorei is found. It seems the braheas must really be in their element at this site. After you have descended into the Jaumave Valley you do not see any more braheas until you approach the drier mountainsides to the south. In these drier environs the braheas appear virtually identical to B. berlandieri as seen in other dry areas farther north. There are plants at Balneario Los Nogales east of Jaumave, in fact, that are growing within a few feet of the Guayalejo River, but only where there is pure limestone lining the riverside.

Brahea ‘Silverback’ West of Villa Mainero

The Brahea above Ciudad Victoria

Brahea aff dulcis (low green clumper) - this variety appears to be present in limited numbers on the mountain pass above Cd. Victoria, where it tends to dissolve into the many other forms found on the road. It is really not found in great numbers until farther south, particularly east of Tula heading towards Ocampo. These plants, according to Dr. Quero, approach B. dulcis more than the other types of braheas found in NE Mexico, though their inflorescences appear very similar to the B. berlandieri found farther north, except perhaps that they are less rigid and angular in their branching habit. Most of them appear completely trunkless from a distance and their leaves are uniformly green. It is not until you see old plants or observe the plants close up until you realize that they do develop trunks, occasionally a few meters tall but mostly the trunks are decumbent along the ground (they are be easily distinguished from B. decumbens, though, by the inflorescence). The plants can apparently even branch along the trunk in some rare instances, another trait shared with B. dulcis. Often what is mistaken for a branching pattern, however, appears likely to be seedlings germinating in the fibers of the old trunks. These traits become more exaggerated as you head south, it is not uncommon to see crawling or even branched braheas in the forest west of Valles. Near El Naranjo, between Cd. del Maiz and Mante, a very similar form appears as shrubs in the understory but will develop into trees if given an opening in the forest canopy. Not only morphologically but ecologically as well these plants are immediately distinct from the single trunked trees known as B. berlandieri. I have never seen these palms in anything other than forest, namely oak forest, usually where there is some amount of soil covering the limestone rocks. The climate is humid and distinctly tropical, with warm sultry nights and plenty of summer rain. While at first it may seem odd that braheas growing in wetter areas would be smaller and shorter, they have evidently found a successful niche as an understory plant, much like the B. decumbens west of Rio Verde. There are herbarium reports of braheas growing in the southern parts of the Sierra de Tamaulipas, it would not surprise me in the least if they are this same type of Brahea. Morris Clint in Brownsville has an old Brahea in his backyard which appears very similar to this form.

A green understory Brahea sp east of Ciudad del Maiz

Left & below - A running/branching type of Brahea aff dulcis west of Valles Lower left - The low clumping green Brahea found east of Tula

Brahea aff decumbens - to the north and east of the northermost known populations of B. decumbens are several populations of extremely interesting dwarf braheas. Superficially they resemble B. decumbens: they have the same low clumping growth habit and generally glaucous leaves. But a closer inspection of them reveals that they are not B. decumbens at all. The inflorescences of these plants are not compact and branched like B. decumbens but are rather long and very slender, much like a smaller version of B. berlandieri . The leaves are also more like berlandieri, they are less stiff and larger, generally more graceful in appearance. I have currently only seen plants like this in two locales, though there are doubtlessly others in these rugged roadless mountains (UPDATE Jan 2004 - I have spotted other similar palms in SW Tamps). Both populations have been collected by botanists and are labeled as B. berlandieri at the UT Herbarium. Brahea ‘El Potrerito’ - this palm had frustratingly eluded me for the past year, getting to it to photograph it in the wild proved a challenge to say the least. Carl and John discovered it in the early 1990s while driving between Puerto Purificacion and Dulces Nombres near a small place on the topo map called ‘El Potrerito’. To reach it requires a long drive down a very rough logging road, difficult when dry and nearly impossible when wet. It bears a superficial resemblance to Brahea decumbens , especially the decumbens seen in the oak forest west of Rio Verde, in a similarly mesic environment. This palm even develops a trailing decumbent trunk like many other dwarf palms of NE Mexico and the leaves tend to be blue but are sometimes greener, particularly when growing in heavy shade. The inflorescence is not tight and branched like B. decumbens but more resembles B. berlandieri , only in miniature, not exceeding a few feet. The leaves are also more like a diminutive version of B. berlandieri or (especially) the silverback brahea, to which it seems most closely related, they are softer than the leaves seen on most B. decumbens. Chamaedorea radicalis also makes an appearance at this site. Brahea ‘Aramberri’ - it was not until a few weeks after I had finally reached the braheas at Potrerito when RL Frasier and I stumbled upon this population to the northeast of Aramberri. Pat MacNeal in Austin had shown me a few pictures of these palms, they looked like B. decumbens from the photos, but had been listed as B. berlandieri at the UT Herbarium. They are hard to miss, all of a sudden you come to a large dry hillside covered with these small blue braheas. A closer inspection, however, reveals that they are not the same B. decumbens that you see to the south of here, their long flower spikes and larger soft leaves are quite different. If you continue on the same road conditions quickly become more humid, and in the shade these palms bear a strong resemblance to the population at Potrerito. The classification of these two populations has yet to be determined, but on an even more recent trip to Tamaulipas it appears more and more evident that B. berlandieri/dulcis can indeed hybridize with B. decumbens. Details will be covered in a future PSST bulletin, but I’m nearly 100% convinced that there are indeed hybrids between the two species, and that even some plants in cultivation may turn out to be hybrids also. It is entirely possible or perhaps even probable that Aramberri and Potrerito are some sort of stabilized population of hybrid origin. It probably, in fact, will prove a better horticultural candidate than “true” B. decumbens, and seed may be easier to obtain.

Above - Brahea ‘El Potrerito’ at Peckerwood Gardens Left - wild plants between Puerto Purificacion and Dulces Nombres on the NL/Tamps border

Brahea ‘El Potrerito’ between Puerto Purificacion and Dulces Nombres

Brahea ‘Aramberri’, Nuevo Leon

Large plant of Brahea ‘Aramberri’, Nuevo Leon

Brahea decumbens - this is probably the most famous indigenous palm from NE Mexico, and while it is closely related to berlandieri/dulcis, it can be distinguished in several ways. The most important difference botanically is its consistently small decumbent habit and the inflorescence, which is shorter and branches more closer to the base of the plant, not developing the longer, more slender, and generally less branched flower spikes of dulcis/ berlandieri. This distinguishes it from very similar clumping forms of the B. berlandieri/dulcis complex which can occur to the north and east. Its habit, apart from being clumping/decumbent (at least in the wild), is almost exclusively blue in color, though some green forms are known to occur near Zaragoza in Nuevo Leon and perhaps elsewhere. Young seedlings of B. decumbens are green and only develop their blue coloration after some time, both in the wild and in cultivation. If you’re lucky enough to find a plant for sale, don’t be surprised if small plants with immature leaves are green. The natural range of B. decumbens appears to extend from southern Nuevo Leon around Zaragoza, through southwestern Tamaulipas near Miquihuana and Palmillas and onto eastern San Luis Potosi (the plant was originally described from plants growing near Guadalcazar north of the city of San Luis Potosi). From there it apparently extends southwards into Hidalgo and perhaps farther south - well out of the region covered in this book. The largest known populations of B. decumbens occur to the south and northwest of Palmillas. There are some especially old and nice specimens on the road to Miquihuana. This area occurs as you exit the more arid Jaumave valley and head into a slightly wetter vegetation where piñon pine and juniper forms a sort of low open forest. In this area are many unique and interesting plants: Nolina nelsonii, Dasylirion quadrangulatum, Mimosa martindelcampoi, Pithecellobium elastichophyllum, the list goes on and on. The ecology of B. decumbens is interesting for sure. Ripe seed is extremely difficult to find, this no doubt contributes to its rarity in cultivation, but the natural populations appear to have no problem reproducing. The plants are certainly slow growing in the wild and appear to be slow in most gardens as well, they sucker and stay completely decumbent - very old plants will develop trunks that run along the ground or perhaps underground for several feet. This habit may be an adaptation to fires; near Palmillas, in fact, it appeared that a major brush fire had caused extensive damage in just the past year or two. On a few hillsides on the way up to Miquihuana it forms large dominant colonies either in full sun or under light shade. It does not appear to occur below about 3000’ above sea level (even though it seems to like heat) and can be seen as little more than a dwarf ground cover approaching the 8000’ elevation mark above Miquihuana - certainly no other palm in NE Mexico comes close to such an altitude.

More curious is its presence in much more humid conditions between San Luis Potosi and Rio Verde at about 45000â&#x20AC;&#x2122; elevation. Here the country is lush oak forest where B. decumbens forms part of a rich understory growth, a very different environment than the much drier region in Tamaulipas. It is also reported near the relatively mesic area around Zaragoza, NL, where a number of green plants can be seen in addition to the typically blue plants seen everywhere else (I did see a single green plant on one of the hillsides covered with B. decumbens on the way up to Miquihuana, and it certainly stood out). Perhaps the most mysterious palms, though, are some of the dwarf braheas seen east of Ciudad del Maiz, in the oak forest on the western edge of the mountains right out of town. These small palms are green with perhaps a slight tinge of glaucous coloring and at first glance resemble most of the other green braheas in the vicinity, but their short branched inflorescence is more reminiscent of B. decumbens than of the B. dulcis type found elsewhere in these mountains. Which species this I do not know, but I would like to visit the site again at some point. For the most part, however, the delineation between B. decumbens and B. berlandieri/dulcis is easily distinguished by its distinct inflorescence and usually, if not always, by the leaf color and growth habit. There seems to be few plants which do not comfortably fit into one group or the other. I am reasonably confident that, in the end, Brahea decumbens will remain a distinct species when the genus gets its long overdue reworking. In cultivation Brahea decumbens is not at all common, no doubt due to the scarcity of seed and its often slow growth rates. Several botanical gardens have it in their collections, including the Huntington in California and of course Peckerwood in Hempstead. Carl reports that it is sometimes tricky to get it started in Hempstead if conditions arenâ&#x20AC;&#x2122;t just right. He also reports that small plants in containers are quite vulnerable to freezing conditions while mature established plants are hardy to pretty severe frosts. By far the largest specimen I have seen in cultivation is at the San Antonio Botanical Gardens, it is a massive plant which appears much larger than any other B. decumbens I have ever seen in cultivation or in the wild. It cannot be terribly old - I assume it was collected by Lynn Lowery, probably in the 1970s, but nobody seems to know the original source. Mountain States Nursery has also grown it to an impressive size in just over a decade, apparently they really like the heat (in full Phoenix sun) and nursery conditions they get in Arizona. That may be a clue for anyone who wants to attempt to grow it.

Brahea decumbens Above right - in oak forest, on the road from Rio Verde to San Luis Potosi Left - an old plant between Palmillas and Miquihuana

Brahea decumbens Right - south of Guadalcazar Below - nearly mature seed south of Palmillas

Left - green plant near La Peña Above - at 7500’ above Miquihuana

Below - Brahea decumbens at the Huntington Botanical Gardens, California

Above - Brahea decumbens at Peckerwood Gardens

Brahea moorei - this little known gem is perhaps the best-kept secret of the palm kingdom from Northeastern Mexico. Not only is it completely distinct from the B. berlandieri/dulcis/decumbens group of palms, it has tremendous ornamental potential for both Texas and other parts of the world. Only described in the 1950s, its closest relative appears to be B. nitida from Western Mexico. In habit and inflorescence it is somewhat reminiscent of Sabal minor, though the palm is certainly more beautiful and graceful in appearance. The flower spike is especially distinctive for a brahea, it can often exceed 8 feet in height even if the parent plant may not be more than three feet tall. This dramatically contrasts to all the other braheas in NE Mexico, which carry their inflorescences inside or to the edge of their leaf crowns but rarely much farther. The main appeal of B. moorei , however, is the foliage, it is a bright apple green with frosted edges on the upper leaf but a gorgeous chalky white underneath, the white powder rubbing off on your hands if handled. In spite of its low habit it also appears to be relatively fast growing for a brahea, at least in humid areas. Carl reports that it grows noticeably faster than B. decumbens in Hempstead and plants have grown to maturity in 10 years from seed. In Northeastern Mexico, Brahea moorei can be tricky to find if you donâ&#x20AC;&#x2122;t know where to look. It took several unsuccessful trips and dead ends before Bruce Erickson of California finally gave me some explicit instructions as to where I could find it on the road outside Cd. Victoria (now I pass by it and wonder how I ever could have missed it, and have even spotted it in a second locale on the same road). Sure enough, when he told me to pull over and start walking it did indeed appear, in decent numbers, but within a very narrow range on the mountain. Chamaedorea radicalis is also relatively abundant just a few hundred feet away, but again is seen nowhere else on the mountain apart from the occasional odd plant. It is much more abundant on the difficult road to Puerto Purificacion, where some plants were old enough to have a similar subterranean trunk such as found on Sabal minor (the Mexican form) or Brahea decumbens. I have also seen a single plant of what I suspect was B. moorei in a wash near Villa Maneiro, which suggests to me that it is more abundant on the higher ridges in the vicinity. It seems to be at its best at elevations of 3000 to 4000â&#x20AC;&#x2122; in NE Mexico, under the shade of oak trees in areas that have sufficient humidity and relatively good soils - it will not grow in bare rock like other braheas. It will rarely occur at lower elevations, probably errant plants which have washed down from higher elevations in the mountains. Its native range does not stop at Victoria, it is known from El Cielo and down into the states of

San Luis Potosi and Hidalgo also. A plant growing at the Huntington which originated from Hidalgo has reportedly branched underground a number of times, that is not seen in the Tamaulipan plants. The degree of the silver â&#x20AC;&#x153;chalkâ&#x20AC;? on the leaves is also reported to be more variable farther south as well. All in all it is one of the Sierra Madreâ&#x20AC;&#x2122;s best palms for ornamental horticulture. Cultivated plants are currently thriving in Hempstead, Dallas, and even Brownsville, and it has potential for use in many areas of the South and California, though I would think they may be harder to grow than, say, B. berlandieri or decumbens in extremely hot regions such as Arizona. Plants are not certainly not readily available, but Yucca-do and some of the very specialized palm nurseries in California usually have it offered for sale. Part of the problem is that it is hard to catch the plants with ripe seed in the wild, though apparently not as tricky as B. decumbens . We did see a few plants with mature seed above Cd. Victoria in the summer of 2003 (as opposed to virtually none with B. decumbens). As with B. decumbens, some animals undoubtedly eat the seed as it matures and then disperse it later. As cultivated plants begin to produce seed I would expect to start seeing it more and more in cultivation, where it will undoubtedly prove very popular.

Brahea moorei Above - on the road to Puerto Purificacion Right - growing under oaks, west of Cd Victoria

Brahea moorei Left - cultivated at Peckerwood Gardens Lower Left - old plant with trunk, near Purificacion Below - above Cd Victoria

Brahea moorei Above - Peckerwood Gardens Right - flowering plants above Cd Victoria

The Nolinaceae of NE Mexico - Dasylirion, Nolina, and related genera Aside from the yuccas and agaves, there is another ornamental group of arborescent monocots which are distinctly Mexican. These are the dasylirions and the fairly closely related genera Nolina and Beaucarnea. The nolinas especially were popular in the late nineteenth century on the European Riviera but are relatively rare in cultivation today, though the closely related common ponytail palm (Beaucarnea recurvata ) is a staple of the modern nursery industry. Only one species of Dasylirion, the so-called Mexican grass tree, has attracted serious horticultural interest around the world. This is a shame, as many of the dasylirions are quite interesting and attractive. Yucca-do and Peckerwood Gardens must be commended for their appreciation and promotion of this wonderful group of plants, they have demonstrated what powerful accents these simple plants can make in a garden, and they have played off their subtle variations in leaf coloration and growth forms to the max. Fortunately, the dasylirions of Mexico and the US Southwest have been well documented thanks to Dr. David Bogler. Bogler lists four endemic species of Dasylirion in NE Mexico. The most notable dasylirion in cultivation from NE Mexico is D. quadrangulatum, formerly D. longissimum (a name now used for a very similar species found farther south). This is the well-known Mexican grass tree seen in nurseries here and elsewhere. It gets that common name from its superficial resemblance to some of the Australian grass trees in the genus Xanthorrhoea . The Mexican grass tree (simply called â&#x20AC;&#x153;sotolâ&#x20AC;? like most of the dasylirions in Mexico) is a graceful, beautiful species with very long, slender toothless leaves and a large imposing flower spike. In the wild their trunks can grow past 8 or 10 feet but I have never seen plants that tall in cultivation. Once taken out in the wild by the thousands, it is now grown from seed by several large nurseries. It transplants poorly and therefore it is recommended that only container grown plants be purchased - for every trunked plant you see in cultivation many more have died after an attempted relocation. It is native to southern Nuevo Leon near Dr. Arroyo and southwestern Tamaulipas, in Brahea decumbens country. There is only other species in the genus in the general area which bears a resemblance to it, D. longissimum var treleasei, which is only known from one small area in San Luis Potosi, at Guaxcama, near Villa Juarez. RL Frasier and I went to Guaxcama in the summer of 2003 and

thought it to look virtually identical to D. longissimum, save a few very small prickles at the base of the leaves and a smaller inflorescence. I have seen a few plants in cultivation which resemble D. quadrangulatum but have small teeth at intervals, I don’t know if they are D. treleasei or are hybrids with other species. Carl has told me that the true D. longissimum found farther south in Hidalgo is even larger than D. quadrangulatum; I’m sure they are impressive indeed and hope to see them in the wild one day. While D. quadrangulatum is the most unique plant in the genus, the other dasylirions in NE Mexico are also ornamental. Another species native to the same vicinity as the Mexican grass tree is D. miquihuanensis. It is a green plant with stiffish leaves whose leaf tips end in a rounded “brush” of dried fibers. Many people confuse this plant with D. acrotriche, which also carries brushy fibered leaf tips but occurs farther south and does not get as large. Older specimens of D. miquihuanensis can develop several feet of trunk, especially in southern Nuevo Leon. If you travel the VictoriaJaumave highway you will first see it on the backside of the front range of mountains, rather suddenly in the brush a very different looking dasylirion with the dried brown leaf tips will just appear ( D. berlandieri is common along this road as well). The plants on the Victoria pass, in fact, have a more distinctive “brushier” tip to them and are for me more ornamental than the plants found closer towards Miquihuana. As you ascend into the mountains above Miquihuana it appears that there is considerable intergrading with D. quadrangulatum, the two species can become hard to tell apart above 6000-7000’ altitude. The most widespread species in NE Mexico is the variable D. berlandieri . It is distinguished from other dasylirions by its usually lax, reclining leaves. Sometimes they can look untidy, but given their variation and usually glaucous coloring (sometimes intensely so), many of the forms can be quite ornamental. It is one of the few dasylirions which does not as a rule form some sort of a trunk. The native habitat ranges from the Sierra de Lampazos just south of Nuevo Laredo down through Monterrey and into Tamaulipas and San Luis Potosi. It grows in fairly humid areas, including the Sierras de San Carlos and Tamaulipas, and is known to occur as close as 20 miles from the Gulf of Mexico in rocky areas. It enjoys some attention from a few Texas nurserymen. Nice specimens can be seen at the San Antonio Botanical Gardens, where some of the individuals are especially blue. Specimens

from the Sierra de Lampazos tend to be larger and more robust and appear to buck the trend and may develop trunks, this form is in cultivation at Peckerwood Gardens. On the road from Tula to Ocampo I have seen what appears to be a completely green form of D. berlandieri. It is also unusual in that the leaves are quite wide and totally lax, they all seem to collapse at the same point. This would make for a dramatic plant on a cliff or slope. A number of plants on the road to Puerto Purificacion also have this very pronounced weeping habit, especially if they are growing on the side of a cliff. Near Dr. Arroyo, towards the drier end of its range, it apparently hybridizes with D. miquihuanensis. I have seen some plants that look like hybrids in the general region and, while interesting, could really not call them attractive. The last species known from NE Mexico is the usually glaucous D. cedrosanum . It is common around the city of Saltillo and points to the northwest and west. It resembles the often-cultivated D. wheeleri from the United States, though it has thicker leaves and is a more robust plant. A form with wider than normal leaves is reported from the Cuatrocienegas area of Coahuila. It is not generally cultivated though the glaucous forms have ornamental value.

Dasylirion quadrangulatum, Mexican grass tree near Dr. Arroyo

Dasylirion quadrangulatum, cultivated near Linares

Dasylirion treleasei near Guaxcama, San Luis Potosi

Dasylirion berlandieri Left - weeping form, the road to Puerto Purificacion Below - Sierra de Lampazos form, Peckerwood

Dasylirion berlandieri Left - very pendulous green form east of Tula Below - extra blue form, Peckerwood Gardens

Dasylirion miquihuanensis Above - between Jaumave and Cd Victoria Left - Peckerwood Gardens

Dasylirion cedrosanum outside Saltillo

Resembling Dasylirion quadrangulatum are several of the trunked Nolina species. There are a number of tall ornamental nolinas from Mexico, two of which are natives in the northeast. By far the better known of the two is Nolina nelsonii. It is commonly seen in southwestern Tamaulipas, if you take the mountain road out of Victoria to Jaumave you can catch a brief glimpse of it just after you’ve made the crest on the mountain pass, but it does not become common until you approach the countryside around Palmillas. In this area it grows in relative abundance. This is the same general area where such interesting plants as Dasylirion longissimum, D. miquihuanensis , and Brahea decumbens are found. Unlike most other large nolinas, this species is a dramatic blue in color and has bold straight leaves. The giant creamy white flower spike is simply stunning in full bloom, better than even the finest yuccas. It apparently is the easiest large of the tree nolinas to grow in Central Texas at least, just give it well drained soil and it seems to be happy (many of the other tree nolinas such as N. longifolia can develop diseases or simply rot here). In cultivation it often gets longer more striking leaves than in the wild, young plants can be particularly impressive and retain their blue coloring if they are the true species. Until recently, Nolina nelsonii was thought to have been the only arborescent nolina from northeastern Mexico. In the 1990s, however, an apparent second species was discovered in the high mountains between Miquihuana and Zaragoza. This as-yet undescribed species has been grown by Yuccado nursery for nearly a decade now, and has been dubbed by them simply as Nolina ‘La Siberica’ after the small town it was found growing near. It is a remarkable plant, primitive looking in appearance, the green crown looks not too unlike a dragon tree ( Dracaena draco), and the leaf tips have a distinct curl which recalls some of the Dasylirion species. It is growing at Peckerwood Gardens in deep shade and has also been grown in North Carolina. Since it generally occurs at elevations over 8000 feet I am surprised that it grows in the southern U.S. at all, the climate is quite cool up there even in the middle of the summer. It is certainly worth growing in a garden but will probably be confined to the cooler winter environs of Central Texas rather than steamier South Texas. What looked like this same species was occasionally seen at lower elevations (4500 ft.?), growing with Nolina nelsonii in some spots. Dr. Luis Hernandez at the University of Queretaro is preparing a monograph on the Mexican nolinas, and according to him this new species can intergrade with N.

nelsonii. There were a few plants above Miquihuana which did look intermediate, but they were few and far between - most of the time the difference between nelsonii and ‘La Siberica’ was very distinct. If anything Nolina ‘La Siberica’ appears closer to N. parviflora from farther south. Since nolinas are dioecious like date palms it is possible that they may well start hybridizing in cultivation, far removed from their native habitat. It would be interesting to see if these nolinas might cross with something like the large impressive Nolina matapensis from Sonora. Closely related to Nolina is the wonderful genus Beaucarnea . The most famous of the genus is B. recurvata from southern Tamaulipas. It typically has several trunks which emanate from a spectacular large swollen base which resembles an elephant’s hide. It can be seen around Gomez Farias in the mountains and is reported also from the washes and creek areas below the mountains. It is well known in cultivation throughout the world, and is often planted outdoors in extreme South Texas. As a landscape plant it is very easy to grow here, all it really needs is good drainage, though in exposed areas a hard freeze can cause the plant to freeze back to that big base. Protected plants will lose their leaves and perhaps a foot or two of upper stem in a bad freeze but recover well. As a general rule I think the beaucarneas on the whole are better suited to South Texas whereas the nolinas are better subjects for Central and maybe even parts of North Texas. Another relative of Nolina and Beaucarnea is the strange plant Calibanus hookeri. It is commonly offered in succulent and caudex nurseries. It basically resembles a large grass but develops a large swollen caudex which is reported to get quite large in the wild. Originally described from Hidalgo, it has been reported from SW Tamaulipas and Nuevo Leon, which would not be surprising since it is known to occur in the Sierra de Catorce in far northern San Luis Potosi, at high elevations (8000+ ft.). This area is due west of Dr. Arroyo in Nuevo Leon and undoubtedly gets quite cold in winter. I think cold tolerance should not be an issue for this plant, though a plant enthusiast in England has told me his plants have rotted in a wet spring there when some of his other Mexican plants survived. Excellent drainage would likely be a key to its success here. It seems to have no trouble with the heat and humidity of a Texas summer.

Nolina nelsonii Above - in bloom west of Palmillas Right - cultivated at Peckerwood Gardens

Above - Nolina sp, Dasylirion miquihuanensis type and Brahea decumbens growing in high pine forest above Miquihuana

Nolina nelsonii Upper left - at the San Antonio Sunken Gardens Lower left - tall plant between Miquihuana and Palmillas

Nolina sp ‘La Siberica’ Above - in cultivation, Peckerwood Gardens Right - in the wild above Miquihuana

Nolina sp ‘La Siberica’ in the wild above Miquihuana

Calibanus hookeri in San Antonio Beaucarnea recurvata in Harlingen

Beaucarnea recurvata near Ocampo

Ornamental Yuccas & Hesperaloes from NE Mexico One of the most distinctive features of the drier warm regions of North America is the abundance of large, often arborescent monocots. No, I’m not talking about palms; they are, of course, prevalent in many warm regions around the globe. The unique and exclusively North American tree monocots belong to none other than the genus Yucca. While the Desert Southwest of the United States is notorious for the much-hyped Joshua trees, there is actually a larger and very common species in Northeastern Mexico, Yucca filifera , once called Y. australis (both names are confusing and may get revised again). Yucca filifera has a vast native range, from near the Texas border (about 30 miles from Lake Falcon) down into Central Mexico. In much of the drier parts of its range it is easily the dominant plant in the landscape. As you head farther south there are other large yuccas which appear very similar, but Y. filifera can be readily distinguished by its pendulous flower stalk. Large old trees are magnificent, the most notable in cultivation being the old giants at the Huntington Botanical Gardens in California. In spite of their close proximity to Texas, they are rarely seen in cultivation here, even though they are apparently hardy as far north as the Pleasanton area just south of San Antonio. They seem easy to transplant and need well-drained soil, really there’s no good excuse for their scarcity here. Even on the Mexican side of the Valley the plant is not as common as you would think. Many of the largest and most abundant Y. filifera grow on the high Mexican plateau in San Luis Potosi. It is also present in smaller numbers on the coastal plains and thorn scrub just south of Texas. They appear to be capable of growing from cuttings, since large fence-like rows of them can be seen in Nuevo Leon, where all the plants are the same height. Sometimes they grow in close proximity to our native Y. treculeana, which can be distinguished by its smaller overall size, lack of “threads” on the leaf edges, and upright flower stalks. Down in San Luis Potosi is Yucca potosina, which may turn out to simply be a variant of Y. filifera. It looks much like Y. filifera but branches rarely if at all, except sometimes at the base. I saw a number of yuccas which fit this general description in the subtropical forest west of Rio Verde on the road to San Luis Potosi.

There apparently is another, recently described yucca from Northeastern Mexico, Y. linearifolia (syn Y. linearis). It has been collected near Saltillo and again down near Rayones in Nuevo Leon. The Rayones population is reported to be pretty rare and bluer than collections from other regions. The leaves are long and very slender, not too unlike Y. rostrata only thinner. It also resembles Y. queretaroensis from farther south but is in fact not closely related to either of those species. It is obviously very rare in cultivation, the only specimen I know of is at Peckerwood Gardens and a few collections in Europe, but it appears easy enough to grow. There are a number of rather slender leaved yuccas between Monterrey and Saltillo for which I have not found a confirmed identity. Two yuccas which are quite common in NE Mexico actually sneak across the border in the Big Bend region of Texas, but are worth mentioning. These are the silvery Y. rostrata and the massive Y. carnerosana. There are also a few unique endemic species from the drier parts of western Coahuila. The diminutive Y. eindlichiana resembles more of a small Hesperaloe than a yucca, and Y. coahuilensis is another small trunkless species which is reported to have rather large flowers.

Yucca linearifolia Above - Peckerwood Gardens Right - culivated near Linares

Right - Yucca filifera north of Dr. Arroyo Below- Y. filifera west of Palmillas

Below - Yucca filifera cultivated in Jimenez

Above - Y. filifera, an old plant at the Huntington

Above - Yucca carnerosana south of Galeana, NL Left - Yucca rostrata in cultivation in Harlingen

Closely related to the yuccas are the hesperaloes. There are five known species of Hesperaloe , including the common Texas native Hesperaloe parviflora, often called red yucca. From Northeastern Mexico come a couple of more species. The most notable is the imposing Hesperaloe funifera from Coahuila. Renegade populations of this dramatic accent plant are also found in western Nuevo Leon and a single population of it was recently found north of Del Rio in Texas. It has large, tall, dramatic straight leaves and long flower spikes, so long in fact that oftentimes you cannot see the flowers. The giant leaves make for a really imposing ornamental in a drier site. Well drained conditions seem to be a must for this plant. An interesting variant of this plant is H. funifera var. chiangii from San Luis Potosi, it seems to have fewer, even stiffer leaves, and they appear to just rise straight out of the ground in dramatic fashion. RL Frasier and I have seen it in drier areas around Ciudad del Maiz (there are also some beautiful ocotillo “forests” in the area, if you’re into that sort of thing). Another species from NE Mexico, Hesperaloe campanulata, looks at first glance to be a smaller version of H. funifera but has a smaller flower stalk similar to our native red yucca. Greg Starr has studied the hesperaloes extensively and has pondered the possibility that H. campanulata may actually be a plant of ancient hybrid origin which has become reasonably stable. Certainly the hesperaloes seem to readily hybridize in cultivation so this does not seem so farfetched. Around Montemorelos I have seen what looks like H. campanulata and it does indeed seem to exhibit variation in leaf and inflorescence size.

Hesperaloe funifera Above - in San Antonio Left - at Caba単as La Florida, Tamaulipas

Hesperaloe aff campanulata Left (upper & lower) - in San Antonio Below - near Montemorelos

The Hechtias of Northeastern Mexico Here is yet another group of plants whose identity in northeastern Mexico is confusing to say the least. From observing numerous populations in NE Mexico it appears that there are two distinct types of hechtias here, a type resembling H. podantha/texensis from the drier areas, and a larger plant from more humid areas which is very close to, if not the same as, H. glomerata, which is a native of Starr County. The hechtias are sorely due for a good revision and these forms will undoubtedly be sorted out in time. The more ornamental of the two is definitely the H. glomerata type. It is predominant in many areas of northeastern Mexico, growing with a number of agaves and Dioon edule, taking advantage of drier, well drained rocky sites where most other plants struggle. It is found both on the thorn scrub plains in rockier soils and (especially) in the Sierra Madre, where the most colorful and interesting forms appear. The best forms seen in the mountains will have especially silvery scales and/or pronounced banding patterns to them, which can really be gorgeous. Perhaps the best display of hechtias I have seen in NE Mexico is (wouldnâ&#x20AC;&#x2122;t you know it) on the road to Puerto Purificacion, where you are riding along what is basically the top of a mountain ridge headed towards the cloud forest, just before you cross the unnerving Paso de la Muerte (The Pass of Death). Here, though you are but a couple of miles from dripping wet ferns and magnolias and sweetgums, this ridge seems to be in a sort of dry microclimate, and the vegetation is much more xerophytic in makeup. It is here that the hechtias are at their finest, many are green underneath but have a fine scaly coating of frosty white on top of the leaves, while others may have the white scales but also have distinctive red and green banded patterns underneath. Truly spectacular. Given their relative ease of cultivation, they are definitely worthy of use in a garden where their spines will not be a problem. The other Hechtia is more common in the drier areas almost everywhere in NE Mexico. Usually it is nowhere near as spectacular as the better forms of the H. glomerata types, but every now and then you will come across a plant that has turned a brilliant wine red, often due to drought stress according to RL. They are quite impressive but I canâ&#x20AC;&#x2122;t guarantee that the effect can be automatically replicated back home.

Hechtia spp Above left - a red form near Palmillas Lower left and above - nicely colored forms on the road to Puerto Purificacion

Some ornamental trees from the Tamaulipan thorn scrub It is very difficult to find shade trees which are suited for long-term cultivation in deep South Texas. The multiple stresses that are imposed on trees here generally assures the failure of most species after a few years or decades. Temperate zone trees will not stand our long summers and salty soils, while tropical trees will thrive here until a bad freeze comes along. The best places to look for potential trees for this area are the Argentine Chaco and our own backyard in Tamaulipas. The following are some of the nicest trees from the thorn scrub region of Tamaulipas and southern Nuevo Leon which have not quite made it up to the border region but grow under similar conditions.

Acacia coulteri - this attractive thornless acacia first appears as a shrub or small tree around the Monterrey area. As you travel farther south it becomes a larger tree. It resembles a large guajillo ( A. berlandieri) but is more showy in bloom, with long creamy flower spikes. It may be slightly tender (thatâ&#x20AC;&#x2122;s probably why itâ&#x20AC;&#x2122;s shrubbier up north), it appears to suffer cold damage similar to our local tenaza ( Pithecellobium pallens) in severe freezes.

Bumelia laetervirens - Tamaulipan coma - if youâ&#x20AC;&#x2122;re familiar with the local coma tree then you could be forgiven for not recognizing this large tree in Tamaulipas. It really looks nothing like our puny tree, it is large and has thick glossy bright green leaves which give it a lush tropical appearance. It occurs natively from southwest of San Fernando (near Cruillas) and southwards. It may also creep into Nuevo Leon in one or two places. It is abundant on the river plains north of Ciudad Victoria and again south of Soto la Marina, where in both places it makes a magnificent large shade tree. There are a number of trees in the Lower Rio Grande Valley, mostly on the Mexican side of the river, though a few can be seen on this side (Mercedes has several trees, and there is a very nice one near Santa Maria). Older plants suffered minor branch dieback in the 1989 freeze but all recovered well. An excellent tropical tree for South Texas, it deserves wider use

Casimiroa pringlei - this is a smaller dense evergreen tree which occurs in Nuevo Leon south of Monterrey and Tamaulipas south of San Fernando. It can be recognized from other evergreens in the area by the trifoliate leaves. It has been grown in south Texas for many decades. Growth is usually poor in a container but plants pick up when planted in the ground. Pretty hardy, I had a small tree withstand the 1989 freeze in San Antonio where it suffered minor branch dieback. Large trees are rarely seen in a number of Texas towns, fruiting specimens are known in Kingsville. The fruits on female trees surely attract the birds but do not smell particularly nice when rotting on the ground.

Acacia coulteri, Rio Verde-San Luis Potosi road

Casimiroa pringlei Above - in Santa Rosa Canyon southwest of Linares Left - cultivated in Alice, TX

Bumelia laetervirens, Santa Maria TX

Diospyros palmeri - this small tree generally resembles our local Diospyros texana but it lacks the smooth peeling bark. Other than that, it is generally more attractive than D. texana , with larger lusher leaves and a slightly faster growth habit. It is seen in southern Nuevo Leon and near the Jimenez area in Tamaulipas and southward. While it should be plenty hardy for most of South Texas, it may have trouble in the worst freezes in Central Texas.

Ehretia tinifolia - A tropical anaqua tree. This handsome, tropical looking evergreen tree from the southern part of Tamaulipas is seen in the wild as far north as the Soto la Marina area. At first glance, most people would not recognize them as related to our anaqua but the similar fruit and especially the distinct “fluted” trunk gives some hint. While they are commonly seen cultivated in Tamaulipas (including Matamoros, mostly trimmed up as poodle trees), it is nearly impossible to find them in Nuevo Leon.

Ficus cotinifolia - A true tropical, this ficus grows up into areas of Tamaulipas where it shouldn’t. It gets punished severely in cold spells such as ‘89 near its northern limits (Jimenez area), even in the somewhat protected canyons of the Sierra Madre near Victoria most of the trees froze severely in the 1989 freeze. Damaged trees, however, come back with a vengeance, which is probably why it grows in areas which get a rare freeze. Large trees can be found in South Texas, even though there are other tropical figs which can stand a bit more cold.

Harpalyce arborescens - believe it or not, this attractive (if not stunning) tree from the Sierra de Tamaulipas area and southwards has been growing in Weslaco for many decades. It has nice thin wavy leaflets. Plants in Weslaco suffered some branch dieback in ’89 but larger trees suffered little permanent damage. Apparently they can naturalize in Weslaco, so they seem happy enough here. There used to be a large specimen at Fairchild before Hurricane Andrew.

Myrcianthes fragrans - this is the tree that was covered in last summer’s bulletin. It’s still one of my favorites and seems to love growing in a typical Valley yard. Add the wonderful trunk and apparent hardiness (it took 14o F in San Antonio with no stem damage) and you have a winner here. It can be seen growing at Cruillas, southwest of San Fernando, on the hill just north of Jimenez and around Soto la Marina and the Sierra Madre of Central Tamaulipas. In the arroyos around Ciudad Victoria which drain the mountains it can be seen growing in the bottom around large boulders. It loves my yard in Olmito, seedlings are coming up all over the place.

Ehretia tinifolia, cultivated in Reynosa

Diospyros palmeri Right - SW of Linares Below - plant in fruit near Cd Victoria

Ficus cotinifolia north of Jimenez

Harpalyce arborescens in Weslaco

Myrcianthes fragrans growng in a creekbed south of Cd Victoria

Myrcianthes fragrans SW of San Fernando (Cruillas)

Myrcianthes fragrans Above -at Cruillas Left - north of Jimenez

Phoebe tampicensis (Nectandra salicifolia ) - the common name of this plant is aguacatillo, and indeed the fruit of this tree does look like a small avocado (theyâ&#x20AC;&#x2122;re both in the laurel family). The leaves, however, more resemble a willow tree, and larger specimens growing out by themselves can be quite handsome. It grows mostly in the Sierra Madre from southern Nuevo Leon and southwards, but it is found on the thornscrub, mostly nearer the mountains but also near the coast if conditions are not too dry. It should be hardy enough for the Valley but may freeze in Central Texas. Growth does not seem to be terribly fast, at least for me near Brownsville.

Prosopis laevigata - most people who travel south of San Fernando realize that, although there are still mesquite trees everywhere, they look a little bit different than the ones in Texas. Thatâ&#x20AC;&#x2122;s because they are a different species, P. laevigata . In shape and overall appearance it closely resembles our local mesquite, but it is easily distinguished by the finer smaller leaves. It also has a more evergreen habit, something that might make it worth considering for cultivation. There are supposed to be a few plants of it in the Robstown vicinity, apparently spontaneous. South of San Fernando and Montemorelos is the approximate transition zone between the our mesquite and this species. In this transition zone most of the mesquites are intergrades between the two species. A hybrid swarm is also said to be present around Robstown.

Wimmeria concolor - slender, clean, and graceful, wimmeria makes an elegant tree with dark green foliage. It is abundant south of Soto la Marina and is also seen in the mountains and more humid thornscrub west and north of Victoria. There are reports of it growing in the San Carlos Mountains but generally it is rare above the 24th parallel. While mostly a forest dweller, I have seen specimens in a creek bed on the flat drier plains NE of Soto la Marina. They are not as large as trees farther south, which makes me slightly apprehensive about its hardiness. The tallest and most elegant trees seem to be just south of Soto, both towards the coast and into the foothills of the Sierra de Tamaulipas.

Above -Phoebe tampicensis west of Cd Victoria Left - near Montemorelos

Prosopis laevigata NE of Cd Victoria

Wimmeria concolor Above - southeast of Soto la Marina Left - west of Cd. Victoria

MAJOR SOURCES & FURTHER READING Some important publications used for these issues - most are available at the University of Texas at Austin libraries Gentes Herbarum Herbarum, L.H. Bailey (Vol. VI Fasc. IV, 1943 and Vol VIII:219 f.90 1951) Taxonomy and phylogeny of Dasylirion (Nolinaceae) (Nolinaceae), David Bogler (1994) - also see Brittonia 50(1) 1998 Some field observations of Brahea in Tamaulipas, Mexico Mexico, Bruce Erickson (Principes, July 1992 Vol. 36 No. 3) Agaves of continental North America America, Howard Scott Gentry (1982) Vegetacion del Sudeste de Tamaulipas, Mexico, Mexico Francisco González Medrano & Enrique Martínez (Biotica 2(2), 1977) Las plantas mexicanas del genero Yucca Yucca, Eizi Matuda (1980) Végétation de la Huasteca, Méxique: étude phytogeographique et écologique écologique, Henri Puig (1976) Flora generica de Arecaceas de México México, Hermilo Quero Rico (1989) Palms of northeastern Mexico, Mexico Carl Max Schoenfeld (Native Plants Journal, Fall 2002 Vol. 3 No. 2) e-copy available online at: nativeplants.for.uidaho.edu Trees and shrubs of Mexico, Mexico Paul C. Standley (1920 to 1926) A revision of the genus Hesperaloe (Agavaceae), (Agavaceae) Greg Starr (Madroño 44(3), 1977) - also Desert Plants 11(4) 1995 Native species of Bauhinia (Caesalpiniaceae) occurring in northeastern Mexico Mexico, B. L. Turner (Phytologia 76(4), 1994)