Bulbous bluegrass

Poa bulbosa (bulbous bluegrass) is a small, densely tufted annual to short-lived perennial grass of the family Poaceae forming compact clumps up to about 60 cm tall, characterised by distinctive swollen, onion-like bulbous bases roughly 1 cm long composed largely of fleshy water-storage tissue, particularly prominent in plants grown in dry conditions. The smooth, hollow, erect culms bear short, narrow, flat to weakly folded greyish-green leaf blades 1–3 mm wide with a long pointed membranous ligule. The inflorescence is a compact to moderately open, ovate to oblong panicle 3–8 cm long bearing leaflike green spikelets with darker, often purplish bases; the species is famously pseudoviviparous, with the spikelets typically proliferating into small leafy bulbils rather than producing viable seeds. Reproduction is therefore overwhelmingly asexual, both through bulbils dispersed from the panicles and through detachment and rooting of the basal bulbs. Native to dry meadows, sandy steppes, rocky slopes, sand dunes, and overgrazed pastures across Eurasia and North Africa, P. bulbosa is now naturalised practically worldwide, including a widespread occurrence across North America.