Avena sterilis
Image: U.S. Department of the Interior
Description
Avena sterilis is a stout broad-leaved annual grass resembling cultivated oats in general appearance (Ivens, 1989).Stem to 1.5 m height, tufted, erect, rarely geniculate, not branching, not rooting at the nodes, nodes sometimes hairy. Leaf blades 60 cm long, 6-14 mm wide, 30-40 times as long as wide, linear, not hairy. Ligule 2 mm long, membranous, truncate, sheath often on lower leaves. Inflorescence an equilateral or slightly one-sided panicle, 15-45 cm long, 8-25 cm wide. Spikelets with 2-5 florets of which only the lowest has a basal scar, pedicelled, disarticulating above the glumes, but not between the florets. Glumes equal, 30-50 mm long, 9-11 nerved. Lemmas 15-40 mm long, 7 nerved, bidentate, the uppermost awnless, the lower two with a 5-8 cm long bent and twisted dorsal awn (Hafliger and Scholz, 1981; Ivens, 1989; Stace, 1997).
The sub-species sterilis differs from sub-species ludoviciana by the larger size of some reproductive parts (spikelets with 3-5 florets; longer glume 32-45 mm; lemmas 25-33 mm; ligule greater than 5 mm) (Stace, 1997).
Propagation instructions - seeds
When the plant first emerges after the first few rains do an initial removal of this plant by holding it at the base and removing the root ball, or by inserting a weed tool at the base and popping up the root ball. If you missed any, do a follow up removal if necessary after a few weeks.
Do a second session targeting annual grasses after the last rains in late October or November to ensure no additional grasses that come up go to seed.