Poa infirma
Kunth Early Meadow-grassResembling P. annua, but typically a smaller and finer plant, not exceeding 20 cm high, with leaves to 10 cm long and 4 mm wide, and ligule to 4 mm long. Inflorescence as for P. annua, spikelets often sessile or subsessile, 2–4.5 mm long; lower glume 1-nerved, c. 1 mm long; upper glume 3-nerved, c. 1.5 mm long; lemma 1.8–2.5 mm long, the 5 nerves densely hairy in the lower half, internerves glabrous; anthers 0.2–0.5 mm long. Flowers mainly Aug.–Nov.
LoM, VVP, VRiv, RobP, GipP, OtP, Gold, CVU, GGr, DunT, NIS, HSF, VAlp. Also naturalised in NSW, ACT, Tas. Indigenous in Europe, widely naturalized. Probably more widespread than records suggest owing to confusion with ubiquitous Poa annua but perhaps more salt-tolerant with several records from saltmarsh and other near-coastal environments as well as inland salt-lakes and slightly salinated land in the north-west. Where P. infirma and P. annua occur together, P. infirma is typically the earlier flowering of the two.
Molecular evidence suggests that Poa infirma is the maternal parent of the hybridogenous, polyploid P. annua L. (Mao & Huff 2012)
Walsh, N.G. (1994). Poaceae. In: Walsh, N.G.; Entwisle, T.J., Flora of Victoria Vol. 2, Ferns and Allied Plants, Conifers and Monocotyledons, pp. 356–627. Inkata Press, Melbourne.
Mao, Q.; Huff, D.R. (2012). The evolutionary origin of Poa annua L.. Crop Science 52: 1910–1922.
