Aira praecox

HABIT Annual. Culms erect; 2–25 cm long; 2–3 -noded. Leaves mostly basal. Ligule an eciliate membrane; 1.5–3.5 mm long; entire; obtuse. Leaf-blades filiform; involute; 0.5–5 cm long; 0.3–0.5 mm wide. Leaf-blade surface smooth, or scaberulous. Leaf-blade apex acute.

INFLORESCENCE Inflorescence a panicle.

Panicle spiciform; linear, or oblong; 0.5–4.5 cm long; 0.2–0.8 cm wide.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels linear; terete; 1–3 mm long.

FERTILE SPIKELETS Spikelets comprising 2 fertile florets; without rhachilla extension. Spikelets oblong to ovate; laterally compressed; 3–3.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes suppressed between florets (florets arising at about the same level). Floret callus pubescent.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma; shiny; gaping. Lower glume ovate; 3–3.5 mm long; 1 length of upper glume; membranous; much thinner above; much thinner on margins; 1-keeled; keeled above; 1–3 -veined. Lower glume primary vein scaberulous. Lower glume apex acute. Upper glume ovate; 3–3.5 mm long; 1.1 length of adjacent fertile lemma; membranous; 1-keeled; keeled above; 1–3 -veined. Upper glume primary vein scaberulous. Upper glume apex acute.

FLORETS Fertile lemma ovate; laterally compressed; lanceolate in profile; 2.7–3.1 mm long; cartilaginous; without keel; 5 -veined. Lemma lateral veins obscure. Lemma surface scaberulous; rough above. Lemma margins involute; covering most of palea. Lemma apex dentate; 3 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.3–0.4 way up back of lemma; geniculate; 3.4–4.3 mm long overall; with twisted column. Palea elliptic; 0.7 length of lemma; cartilaginous; 2 -veined. Palea apex obtuse.

FLOWER Lodicules 2; lanceolate; membranous. Anthers 3; 0.25–0.3 mm long. Stigmas 2; protandrous; laterally exserted.

FRUIT Caryopsis with adherent pericarp; fusiform; isodiametric; biconvex; estipitate; without sulcus; smooth; apex unappendaged. Embryo 0.2 length of caryopsis. Hilum punctiform. Endosperm farinose. Disseminule comprising a floret.

DISTRIBUTION Europe: northern, central, southwestern, and eastern. Africa: Macaronesia. Asia-temperate: Caucasus and western Asia. Australasia: Australia and New Zealand. North America: western Canada, eastern Canada, northwest USA, northeast USA, southwest USA, and southeast USA. South America: southern South America. Antarctic: Subantarctic islands.

NOTES Aveneae. TAC.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.