Curlytop Knotweed
Polygonum lapathifolium
Growing in damp soil along Mesquite Wash, Maricopa Co., Arizona, USA on 01 Aug. 2009.
ANNUAL HERB: Upright stems rise to 1 meter
or 1½ m before flowering. The stem nodes are swollen and the stipules at
leaf bases are fused into a translucent, light brown, papery sheath that encircles the stem.
LEAVES: Leaves are elyptic and alternate on stems.
RANGE: Commonly encountered in the Sonoran Desert in damp or wet soil in
riparian zones or agricultural ditches. Distributed generally all over North
America.
FRUIT: Dry, single-seeded capsules - the seeds are shiny and flattened.
FLOWERS: Pinkish flowers are small in long, drooping spikes at top of
plant. Flowering mostly late spring through autumn.
UNARMED.