Common name: Spinyhead Sida
Sida acuta Burm.f. APNI*
Description: Perennial shrub to 1.5 m high, slender, erect or spreading, fibrous to woody, stems with fine stellate hairs.
Leaves narrow-lanceolate, 2–9 cm long, 5–40 mm wide, glabrous or wiith fine hairs on margins, crenate; stipules of unequal length.
Flowers solitary or occasionally in crowded heads in the leaf axils. Corolla 6–9 mm long, yellow. Calyx 6 mm long, acuminate.
Fruit 3–5 mm diam.; mericarps 5–8, wedge-shaped and deeply indented on both sides, rounded on back, with 2 sharp awns.
Flowering: Flowers mid to late summer.
Distribution and occurrence: Widespread weed of pastures and crops, seeds prolifically. One recent collection in Sydney. Native of C Amer.
NSW subdivisions: *CC
Other Australian states: *Qld *W.A. *N.T.
Text by A. S. Mitchell & E. H. Norris
Taxon concept: Flora of NSW 1 Suppl. (1999)
APNI* Provides a link to the Australian Plant Name Index (hosted by the Australian National Botanic Gardens) for comprehensive bibliographic data
***The AVH map option provides a detailed interactive Australia wide distribution map drawn from collections held by all major Australian herbaria participating in the Australian Virtual Herbarium project.