Sida acuta Burm. f.

Etymology Genus Greek for water lily or promegranate, but now used for this unrelated genus
Species Having sharp angles; perhaps referring to the awns of the carpels
Family Malvaceae
Synonyms -
Common Names Spiny-head Sida
Status Undetermined
Form Shrub
Native Distribution Obscure


Sida acuta is a shrub easily identified with its serrated leaves and yellow flowers. It is very similar in appearance to Sida rhombifolia, with the exception of its shorter flower stalk (< 1cm) and the seed (more accurately a mericap) having 2 pointed beaks instead of 1 or none (Holm et al., 1977).

Interesting Facts:

The Spiny-head Sida has deep tap roots which helps it to "withstand drought, mowing, or shallow infrequent tillage" (Holm et al., 1977).

A small outgrowth of the Spiny-head Sida.

Flower buds. Note short flower stalk.

Serrated leaf. Note that they are variable in shape.


Seeds with 2 pointed beaks.


Holm LG & Plucknett DL & Pancho JV & Herberger JP. (1977) The World's Worst Weeds: Distribution and Biology. East-West Center/University Press of Hawaii. 609 pp.

Author: Jake
Posted: 2014-11-08 / Modified: 2019-08-27