| Onion twitch (Arrhenatherum
elatius) is a distinctive, common and widespread weed species in
Tasmania, mostly in disturbed areas. It is a large, loosely tufted
grass. The distinctive features are that the plant has a line of
bulbs at the base of the stem, and the flowers. The inflorescence is
a loose panicle that tends to bend over near the top. The spikelets
are widely gaping when mature and about 5-10 mm long, the glumes are
transparent, one flower in the floret has an obvious awn about 15mm
long. The awn is bent near the middle and attached in bottom third
of the lemma. The awn on the other flower in the floret is
inconspicuous. This species can be confused with another common
weed, oatgrass (Avena spp). Avena
has similar inflorescence and growth habit, though the spikelets are
distinctly larger (with glumes at least 15mm long, compared to less
than 10mm in Arrhenatherum). |
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