1. This account presents information on all aspects of the biology of Poa nemoralis L. (Wood Meadow-grass) that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history, and

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... 2. The grass Poa nemoralis is widespread and frequent to locally common across the British Isles, except for western and central Ireland, and northern Scotland. In both its native Eurasian range and introduced ranges in, for example, the Americas, its main habitat comprises temperate (mixed) deciduous woodland. The species finds important secondary habitats in hedgerows, as well as in non-woodland vegetation such as on cliffs, screes and walls or sporadically in grassland and heathland. Although not always taxonomically or morphologically distinct units, the species is suspected to comprise many cytological races and hybrid polyploid populations with variable morphology. Morphological variation among P. nemoralis populations may also be a sign of local environmental adaptation or a result of introgressive hybridization with other, morphologically variable members of Poa section Stenopoa such as P. glauca, P. compressa or P. pratensis. 3. Poa nemoralis is a small-statured, loosely caespitose grass, with populations ranging from a few individual tufts to those visually defining the aspect of the herbaceous understorey. The species tolerates moderate to deep shade on the forest This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. | 1751 Journal of Ecology PLUE Et aL. Wood Meadow-Grass. Poaceae. Poa, section Stenopoa Dumort. Poa nemoralis is a loosely caespitose, perennial grass with epigeogeneous rhizomes. Branching of vegetative shoots basal, all or mostly extravaginal. Culms to (15)30-80(90) cm, mostly erect, sometimes geniculate, slender, smooth below the panicles, 3-5 noded; nodes slightly compressed, turning from green to light brown at maturity, the top node positioned at c. 1/2-3/4 of the culm length. Culms terminating in a slender to moderately stout panicle, with 2-6 ascending to widely spreading branches. Sheaths terete, closed for the lower 10%-20%; bases of basal sheaths glabrous. Ligule (0.1)0.2-0.5(1) mm long, sparsely to densely scabrous, apices truncate, minutely ciliate. Ligules comprising three cell types: elongated long cells, shorter long cells near edges and unicellular prickle hairs. Leaf blades 1-3 mm wide, lanceolate, mostly flat, 5-12 cm long, smooth or weakly rough, more or less abruptly ascending to spreading, straight or ultimately somewhat lax; apex abruptly acute or acute. Panicles (3)7-20 cm, usually erect, lax in shade forms, narrowly lanceoloid to ovoid, slightly to moderately congested; lowest nodes with 2-6 branches. Spikelets solitary, 2.6-4.0(8.0) mm, narrowly lanceolate to lanceolate, laterally compressed, usually not glaucous. Fertile spikelets pedicelled. Pedicels 0.5-6 mm long. Florets (1)2-5 per spikelet. Glumes persistent and slightly unequal, shorter than spikelet, lanceolate, distinctly keeled, keels smooth or sparsely scabrous, apices sharply acute to acuminate. Lemmas 2.4-4.0 mm; proximal lemma narrowly lanceolate to lanceolate, distinctly keeled. Palea about as long as lemma, keels scaberulous. Callus bearing distinctive webbed hairs. Anthers 3, 1-2 mm long. Caryopsis with adherent pericarp, enclosed in the hardened lemma and palea. The information in this section is mostly derived from