neglectum and M. armeniacum in the field Terry & Helen Moore

TERRY & HELEN MOORE

Breckland is a rare and remarkable area of low nutrient alkaline and acid soils that are said to be reminiscent of true deserts. Forty-three percent of Breckland is protected at a national or international level for its wildlife or geological interest. The Breckland Biodiversity Audit 12, (Dolman et al., 2010) found that 28% of the priority S41 species in the UK occur in Breckland and 72 species have their UK distribution restricted to or their primary stronghold in Breckland. The Breckland Flora Group (BFG) was set up with the aim to help these plants to survive and spread using a network of trained volunteers to monitor the plants and work alongside experts.

The Grape-hyacinth (Muscari neglectum) is one of these Breckland specialities and until recently was listed as Vulnerable in Britain (Cheffings & Farrell, 2005) and therefore monitored by the BFG1. It has

1 It has now been moved to the Parking List, a holding area for Red Data Book species now presumed to be neophytes. Above: Muscari neglectum (Grape-hyacinth) in Breckland habitat at Wordwell, West Suffolk (v.c 26). Photographs by the author.

a common garden relation (Garden Grape-hyacinth M. armeniacum) and an introduced naturalised relation, the Compact Grape-hyacinth (M. botryoides), which is scattered and rare and was not considered in this investigation. A variety of sources have written about the differences between M. neglectum and M. armeniacum but many of the BFG volunteers have found problems in identifying between them without side-by-side comparison between the two species. In particular, the different flower colours or shape noted by Stace (2020), and others (Blamey, 2013; Easy, 1998; Harrap, 2013; Rose & O’Reilly, 2006) are not easy to use for those volunteers not familiar with M. neglectum, especially as the colours can vary with age and references to comparative length or width were not useful for plants found in poor Breckland soils.

Finally, after much discussion, it was decided to design a set of questions which would lead us to a simple way to distinguish between the two species in the field. This approach was apt in its timing as several of our volunteers used the first Covid-19 lockdown (in 2020) to apply the questions to the garden form and there was just enough easing the following year (2021) to visit local sites containing known and confirmed M. neglectum.

The situation was complicated by the publication of Alan Leslie’s superbly researched Flora of Cambridgeshire which mentions sites with Muscari containing plants which are intermediate between M. armeniacum and M. neglectum and thought to be hybrids. However our project continued, knowing (or rather hoping) that most of Breckland sites used were not near enough to garden varieties and with the hope that if an intermediate turned up, it could be recognised.

This report reviews the first two years of study during Covid restrictions. Having chosen a site and a group of plants, volunteers were asked to choose not more than five plants per plant group and for each plant to measure: • the length of the longest leaf and its maximum width, • • the total length of the flower stem and the length of the raceme.

Those measurements were used in all combinations to calculate ratios.

Separately they were asked to count the number of leaves attached to the bulb and the number of veins showing on the back of a leaf, both used by Poland & Clement (2020). Finally they were to look at the mid-leaf cross-sectional shape of the longest leaf and allocate it one of the mid-crosssection shapes shown in Figure 1. Counting the number of leaf veins was made easier by cutting a 1cm or 2cm middle section of the longest leaf and sticking the flattened section on a piece of card with double-sided Sellotape with the underside of the leaf upwards. Counting normally takes at least a 10× or 20× magnifying lens so is easier to count

Muscari armeniacum (Garden Grape-hyacinth).

from an enlarged photograph, especially for very small plants found on very poor Breckland soils. The veins became clearer if the completed cards were left for a few hours or overnight to dry slightly. A German text (Jager et al., 2013) suggested that certain measurements from dissected flowers were different between the two species but this proved to be an unreliable field operation so any results were rejected. The scent which several authors mention was tried but several of our volunteers could not detect any scent at all before one of our number found a

Figure 1. The mid-leaf cross-sectional shapes that the researchers were asked to match.

text saying that the scent was much stronger in the evening. This was found to be true, so became a recommendation for our investigation.

All results were all entered into a spreadsheet for automatic counting and calculations. It was assumed that the spread of all numerical properties followed a simple normal, bell-shaped, curve from which the average and 2× standard deviation of each of the species were calculated and examined for overlap. Statistically this includes 95.4% of all results if they do follow a normal distribution. This crude but quick measure allowed judgement as there was insufficient data to use more complex formula-based conclusions.

The results are discussed in three parts: (i) those features needing judgement of leaf shape, flower colour and scent, (ii) calculation of ratios and (iii) those relating to simple counts.

Leaf shape, flower colour and scent The shapes of the longest leaf at its mid-section were different. M. armeniacum had 21 out of 31 returns choosing the profile of ‘c’, with the rest split having 3 for ‘a’ and 7 for ‘b’. However 30 out of 32 M.neglectum chose ‘a’ with ‘b’ taking the other 2. There is an agreement of leaf shape ‘a’ for M. neglectum by Harrap (2013), Stace (2019) and Rose (2006) but no description of the M. armeniacum leaf is included which, according to our returns, is different.

Most books quote colour of the raceme as a potential identification feature but this can be difficult for those unfamiliar with the plants without having examples side by side. Stace (2019) describes sterile flowers being paler, which complicates the identification, so we had decided to look at the colour change from top to bottom of the raceme (Blamey, 2013; Harrap, 2013; Poland & Clement, 2020; Rose & O’Reilly, 2006) rather than trying to estimate absolute colours. This was slightly successful with 13 considered the base of M. neglectum to be darker with 7 returning no change, however only 9 considered that M. armeniacum was darker at the base, with 19 returning no change.

The scent was most interesting as some authors consider the scents of the two species to be an identifying criterion, including Rose & O’Reilly (2006) which quotes M. neglectum as plum-scented, and M. armeniacum as scentless. Plant Crib (Easy, 1998) mentions the starch scent of M. neglectum and that M. armeniacum is scentless to most people. Initially our volunteers described a mixture of descriptions where scent could be detected but when changing the procedure to an evening scent it became detectable. M. armeniacum was principally thought to be faint but unpleasant and sweet, and when asked if either species smelt like starch there was some agreement for M. armeniacum but not for M. neglectum, which was the converse of Plant Crib. Following discussions, M. neglectum was considered to have a scent like Parma Violets.

Ratios The analysis of ratios seems to have no value and was not taken further as clearly the original properties can vary independently.

Counts Two potential simple counts were looked at. Firstly the number of leaves per bulb (without digging them up) and then the number of veins seen on the back of a leaf (Figure 3). Poland & Clement (2020) and Harrap (2013) suggests a range of 3–6 leaves per bulb for M. neglectum for which our average of 4.97 is comfortably within, but the value of 5.35 for M. armeniacum was outside the large range of 6–18 of Poland & Clement (2020). However, this was considered difficult without digging the bulbs up so there were few results.

The most interesting measurement was the number of veins seen on the underside of a leaf. Poland & Clement suggest that M. armeniacum has 10–15 veins and M. neglectum has up to 10. Our averages of 13.46 and 8.66 appropriately agree well, although the range of the 2× standard deviation and the plot of data values (Figure 2) both bridge 10. It would be interesting to know if the hybrids have an intermediate number of veins.

18

16

14

12

Frequency 10

8

6

4

2

0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 No. of veins Figure 2. The number of veins on the back of the middle of the longest leaf plotted against the frequency of occurrence. Figure 3. This shows the veins from two examples of a leaf from M. neglectum (outside sections) and two from M. armeniacum (middle sections) both flattened and stuck on double-sided Sellotape. Those from M. neglectum have been enlarged slightly.

This study has isolated some promising measurements, all of which are simple enough to do in the field, although the number of veins needs a little prior planning to use our method.

Two criteria seem to be useful indicators of which Muscari species has been found. The first is simply to look at the cross-sectional shape of the middle of the

M. neglectum M. armeniacum

longest leaf illustrated in Figure 1. M. neglectum was found to have a curled-into-a-slender-cylinder ‘a’ shape compared to M. armeniacum which had the flattish ‘c’ shape. The second is the colour change of the raceme from top to bottom which appears to be becoming darker for M. neglectum compared to no change for M. armeniacum. The two more seemingly exacting and reliable methods need a little more effort. The first is scent but the plant needs to be visited in the evening to get the full effect. M. neglectum has a scent similar to that of Parma Violets and M. armeniacum is not very pleasant. The second method requires a 10× or even 20× hand lens to look at a mid-section of the longest leaf (and possibly others). The leaves for M. neglectum in our study had fewer than 11 veins whereas M. armeniacum had more than 11. This is only a little different from Poland & Clement (2020) who use up to 10 for M. neglectum and 10 to 15 for M. armeniacum. We believe that this study will make the identification of M. neglectum much easier and more accurate for occasional botanists, not just serious ones, and we hope that this will result in the discovery of more sites of the rare plant. Table 1 summarises the criteria that BFG volunteers now use. Meanwhile it is hoped that an easy test for the hybrid can be found soon.

Thanks are due to members of the Breckland Flora Group (Philippa Goodwin, Johanna Jones, Julia Masson & Anna Saltmarsh) for their help and

Table 1. Final guidance table for distinguishing between Muscari neglectum and Muscari armeniacum. Be aware of sites with both, as Alan Leslie has found several examples of hybrids, and their properties are unknown. Attribute Muscari neglectum Muscari armeniacum Guidance notes

Individual flower – colour Light blue to darker violet blue going down the flower, i.e. lower fertile flowers are darker Bright blue, with no darkening of lower fertile flowers. Becomes paler with age. An indication only as flower colours vary with age and pollination state.

– scent Parma Violets Mild, sweet Scent much stronger in the evening and a good property to separate the two (if you know Parma Violet scent).

– shape

Longest leaf – mid-section shape Oval-shaped More rounded An indication if you have both species close together

Curled into a slender cylinder, grooved on one side Flattened A relative, but fairly accurate, property

– no. of veins on the underside (numbers given are from Poland & Clement (2020). Use a 10× or 20× lens. 10 or fewer veins More than 10 veins Almost 100% accurate. Use a piece of cardboard with double sided tape to stick down a middle piece of flatted leaf, so that the underside is upwards. Becomes easier to see if left for 1–2 hours.

advice, especially Johanna Jones whose enthusiasm drives the project forwards.

Blamey, M., Fitter, R. & Fitter, A. (2nd ed). 2013. Wild Flowers of Britain and Ireland. Bloomsbury, London. Cheffings, C.M. & Farrell, L. (eds), Dines, T.D., Jones, R.A.,

Leach, S.J., McKean, D.R., Pearman, D.A., Preston, C.D.,

Rumsey, F.J. & Taylor, I. 2005. The Vascular Plant Red

Data List for Great Britain. Species Status 7: 1-116. Joint

Nature Conservation Committee, Peterborough. Dolman, P.M., Panter, C.J. & Mossman, H.L. 2010. Securing biodiversity in Breckland: guidance for conservation and research. First Report of the Breckland Biodiversity Audit.

University of East Anglia, Norwich. (www.nbis.org.uk/sites/ default/files/documents/BBA_Report_MainReport.pdf) Easy, G.M.S. 1998. Plant Crib, Muscari (BSBI Plant Crib website: https://bsbi.org/plant-crib). Harrap, S. 2013. A Guide to the Wild Flowers of Britain & Ireland.

Bloomsbury, London. Jager E.J., Muller F., Ritz C.M., Welk, E. & Wesche, K. 2013.

Rothmaler Exkursionsflora von Deutschland, Gefässpflanzen:

Atlasband (12th edn). Springer Spektrum. Poland, J. & Clement, E.J. 2020. The Vegetative Key to the British

Flora (2nd edn). John Poland, Southampton. Rose, F. & O’Reilly, C. 2006. The Wildflower Key (2nd edn).

Frederick Warne/Penguin Group, London. Stace, C.A. 2019. New Flora of the British Isles (4th edn). C & M

Floristics, Middlewood Green, Suffolk.

Breckland Flora Project