POA PRATENSIS SUBSPECIES SUBCAERULEA, in N. GLAMORGAN AND S. BRECON. D. M. BARLING, Royal Agricultural College, Cirencester THESE notes are an account of the distribution and field characters of Poa pratensis L. subspecies subcaerulea (Sm.) (Tutin) in the hill country of north Glamorgan and south Brecon. Before dealing with the details it is worth recounting the taxonomic opinions of the species, for Poa pratensis is classified by some (Akerberg 1942, Gustaffson 1947, and Tutin 1952) into at least four subspecies or form-complexes, whilst Hubbard (1954) in his classical account of the British grasses considers that the three subspecies present in this country are sufficiently distinct to merit separate specific rank. Thus subspecies subcaerulea is sometimes referred to as Poa subcaerulea (Sm.), and yet again is often listed as subspecies irrigata (Lindm.) Lindberg f. However, although there is debate about the rank of the taxon, its characteristics are well appreciated and have been described by Hubbard (1954). It is frequently found in moist soils at varying elevations, and in such diverse habitats as coastal sand- dunes and mountain grasslands, and abroad it has been studied by Love (1952) and Akerberg (1942), though Melderis (1955) com- ments that no work has been done on the populations in this country. Thus the present collections are an attempt to gather some in- formation as a preliminary to more detailed transplant studies. Hyde and Wade (1934) have already recorded the subspecies in Monmouth, Glamorgan, Brecon and Anglesey. During collection in these hill areas subcaerulea has been found in a considerable variety of habitats, and these are listed below (1) Permanent grasslands It has been found in both enclosed and unenclosed grasslands where Agrostis tenuis is dominant and Festuca ovina and F. rubra are present. In these pastures the plants are poorly tillered and most noticeable when the panicles have emerged. Subcaerulea is very common on road verge grazings along open mountain roads where sheep grazing may be intensified in narrow strips, and where Nardus stricta and Molinia caerulea become dominant further away from the roads. (2) Sheep shelters Where localised shelter or camping is taken by sheep, as under walls, banks, or stunted hawthorn, then heavy trampling and faeces concentration results in localised modification of the flora. On these small areas bare ground is obvious and subcaerulea is frequently found, often in well developed mats, together with such species as Agrostis tenuis, Poa annua and Stellaria media. These local modifications are often much isolated amongst large acreages of Nardus grazings. (3) Pathways In the area of study it is often possible to find subcaerulea on sheep and cattle paths. When found, the plants tend to be much more heavily tillered than in the adjoining grassland.
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