Present on Pacific Islands?  yes

Threat only at high elevations?  no

Habit:  herb

Description:  "Freely branching annual mostly 3-5 (10) dm tall, the stem loosely villous or villous-hirsute, especially upward, with rather long, multicellular hairs; leaves sessile or contracted to short, more or less petiolar base, blade elliptic or nearly rhombic to obovate or ovate, evidently to scarcely toothed, mostly 2.5-8 cm long, 1.2-4 cm wide, sparsely or moderately hirsute with more or less appressed to loosely spreading hairs shorter and firmer than those of stem, heads essentially sessile; outer involucral bracts 3-5 mm long, notably villous-ciliate on margins, less hairy or glabrous on back; "fruits" (mature inner involucral bracts) radially somewhat compressed, obtriangular in side view, resinous-glandular, and beset with stout, often apically finely hooked prickles, the body commonly 3.5-5 mm long exclusive of the 2 to several larger prickles about top"  (Wiggins & Porter, 1971; pp. 308-309).

Habitat/ecology:  "A weed of coastal Ecuador and Peru" (Wiggins & Porter, 1971; pp. 308-309).

Propagation:  Seed

Native range:  Ecuador and Peru (GRIN)

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Ecuador (Galápagos Islands) Floreana Group	Floreana Island	probably introduced invasive	Charles Darwin Research Station (2005)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Ecuador (Mainland) Ecuador	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2008)
Perú Perú	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2008)

Comments:  Probably not native to the Galápagos Islands, possibly introduced, per Charles Darwin Research Station.

Additional information:
Additional online information about Acanthospermum microcarpum is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Acanthospermum microcarpum as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Acanthospermum microcarpum may be available from the Germplasm Resources Information Network (GRIN).

References:

Charles Darwin Research Station. 2005. CDRS Herbarium records.

U.S. Dept. Agr., Agr. Res. Serv. 2008. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Wiggins, I. L./Porter, D. M. 1971. Flora of the Galapágos Islands. Stanford University Press. 998 pp.