Avenua fatua, L. and other Graminae records for Suffolk

AVENA

FATUA,

L., AND OTHER GRAMINEAE RECORDS FOR SUFFOLK P . J. O .

TRIST

Avena fatua, L., Spring or Common Wild Oat. HIND 1889, records Avena fatua for 18 parishes. In addition there are three parish records for A. pilosissima, Gray, which is now named var. fatua and one parish record for A. intermedia which is probably A. sativa X A. fatua.

There may have been some confusion in the recording of the two former, nevertheless it is interesting to compare the distribution as we find it today.

The Spring Wild Oat is a weed of arable and disturbed ground and whilst the seeds will remain viable for several years under grassland, there is no germination until the sward is ploughed.

Today there is probably no single parish in Suffolk where the Spring Wild Oat does not grow. It is more prevalent on the loams of the boulder clay than elsewhere, but is also found on arable land in the Pens, the Breckland and on the light sandy soils of both East and West Suffolk.

There are three varieties. Avena fatua var. fatua has the lower half of the lemma covered with long silky hairs and the seed is golden brown in colour. The third seed is usually glabrous.

In var. pilosa Syme there are only a few long white silky hairs on the lower half of the lemma and which are usually found surrounding the base of the awn on the first seed and are generally absent on the second and third seeds. In var. glabrata Peterm, all seeds are glabrous. All of the seeds in the three varieties are awned, with a tuft of hairs at the base and with a basal scar. In Avena ludoviciana Durieu, the basal scar is found only on the first seed and there is no awn on the third seed.

The distribution of var. fatua and var. pilosa is similar and, in many cases, both are found in the same field. I have records for var. fatua in 28 parishes and for var. pilosa in 24 parishes. T h e var. glabrata is apparently very much less common in the two counties and so far I have found it only in a crop of wheat at Holmhill, Old Felixstowe, which may or may not be an indication that it prefers the coastal area.

As an arable weed, the Spring Wild Oat is a considerable problem, in spite of the introduction of spray chemicals. In the lens and on all types of sands in the two counties it is not so serious a problem as it is on the loams of the Boulder Clay. From Haiesworth north west through the parishes of the Saints and south west to Eye and in a line as far south as Framlingham, fields of wheat, barley and peas can be seen to be fĂźll of the Spring Wild Oat.

346 Transactions of the Suffolk Naturalists',

Vol. 12, Part 5

Brornus diandrus Roth., Great Brome.

Recorded by Trist Trans. S u f f . Nat. Soc., XII, pt. I, 58, 1961.

I now find this grass is firmly established, particularly in West Suffolk. It is abundant on road side banks in four minor roads in the parish of Thurston ; in hedge bottoms on Rymer House Farm, Bamham and on the edge of old pits and arable land at Neville House Farm in the parieh of Culford. At Lakenheath there is plenty in a vacant building plot. In East Suffolk, it is abundant on a steep roadside sandy bank in Hasketon. Undoubtedly it has in the past been overlooked for Brornus sterilis.

Bromus tectorum L., Drooping Brome.

A rare Breckland grass. Hind records in sandy fields, Thetford 1886 : Simpson Trans. S u f f . Nat. Soc., XI, pt. 1, 1958. Found in 1963 by Mark Rutterford in open ground on abandoned breckland arable at Little Eriswell.

Bromus secalinus L., Rye Brome.

Recorded by Simpson Trans. S u f f . Nat. Soc., XI, pt. 1, 1958.

Dried specimens seen in 1963 and collected by J. Marshall of Ixworth from field of wheat at Park Farm, Stanton, 1952.

Arrhenatherum elatius (L) J. & C. Presl, Tall Oat Grass.

A very common grass on all soil types throughout the county.

T h e var. subhirsutum also appears on a wide ränge of soils found from Bury St. Edmunds to Framsden ; in the south on heavier land at Raydon and on light sand at Culford. The forma biaristatum is much less common and so far I have only found it in the parishes of Culford, Little Eriswell and Icklingham.

Poa augustifolia L., Narrow Leaved Meadow Grass.

This grass is plentiful in ungrazed Breck heath grassland between young Pines on the west of the King's Forest in the parish of Culford and approached from Neville House Farm.