Cyperus difformis, a
15-40cm-tall annual, grows on paths between paddies or edges of
ditches. Leaves are 2-5mm-wide linear-shaped, shorter than stems,
and have yellow-brown sheaths. Stem tips with 2-3 bracts of the same
shape as the leaves, among which 1 to 6 branches, set about
1cm-in-diameter spikes made up of spherically gathered many
spikelets. The spikelets are 0.3-1cm long, flat-linear, with 10-20
florets arranged in two rows. Bloom time: August-October.