whorled pigeon grass
Tropical & temperate regions
This is an annual loosely tufted grass to 1 metre high usually with stems bent like a knee near the base.
Leaves have a sheath. The leaf stalk is smooth, long and upright with a ligule densely hairy (like eyelashes) and a flat, hairless blade. The base of the leaf stalks are red tinged.
Inflorescence (a group of flowers) is cylindrical and purplish in colour. Bristly seed clusters have short protuding spikes. Seeds are green to purple. One bristle is at the base of each spikelet; the bristle has backward-pointing barbs for attaching to animals and clothing.
Other plants easily confused with this plant
S. glauca (pale pigeon grass) and S. viridis (green pigeon grass) are similar to S. verticillata (whorled pigeon grass). Pale pigeon grass has a higher density of inflorescence (flower spikes). Green pigeon grass has a shorter inflorescence.
Sources & References
"Weeds - an illustrated botanical guide to weeds of Australia" by B. A. Auld and R. W. Medd
"Gardener's Companion to Weeds" by Suzanne Ermert and Leigh Clapp
Prepared by Justin KY Chu, July 2005
Updated by Bev Debrincat, September 2010