Pacific Island Ecosystems at Risk (PIER)

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Blainvillea gayana
Cass., Asteraceae
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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Other Latin names:  Wedelia gossweileri S. Moore

Habit:  herb

Description: 

Genus: "Erect hirsute annual herb with striate angular stems and branches; leaves opposite or alternate above, broadly ovate, acuminate, very shortly cuneate and 3-nerved at base, 5-12 cm long, 3-6 cm broad, thin, pilose on the nerves and veins, shallowly crenate-serrate; petiole slender, pilose; flower-heads pedunculate at the ends of the shoots, or axillary; peduncles variable, up to 4 cm long; capitula oblong in flower, hemispherical in fruit, about 1 cm long; outer involucral bracts lanceolate, acute, thin, striate-hairy outside, inner glabrous; ligules of outer female florets 1 mm long, white; achenes blackish, sharply angled, the outer3-angled with 3 persistent but fragile barbellate aristae, the inner 2- or 3-angled, longer than the outer, with 2 aristae, all transversely rugulose, truncate at apex."  (Hutchison and Dalziel, 1963)

Species:  "An erect hairy annual 1-3 ft. high with white flower-heads about 1/2 inch long" (Hutchison and Dalziel, 1963; p. 237).

"Erect annual herb. Stems covered in rough hairs. Leaves (sub)opposite, elliptic to ovate with a rather long pointed tip, up to 13 x 8 cm, 3-veined from the base, sparsely hairy; margin serrate-crenate. Capitula somewhat long and narrow, c. 1.2 x 0.5 cm. Involucral bracts c. 1 cm long, oblong-elliptic, hairy and glandular on the outside. Florets whitish, sometimes with short, inconspicuous 2-3-toothed rays"  (Flora of Mozambique online).

An erect annual herb growing to about 2 m in height.  It has opposite, dull green leaves that are softly pubescent beneath.  The upper stems are purplish.  Inconspicuous mauve florets are subtended by several rows of pale green involucral bracts.  The mature achenes are dark brown, ca 5-7 mm x 1.5-2 mm with a rough-textured surface and surmounted by 3 bristles up to 2.5 mm long. (Barbara Waterhouse, AQIS, personal communication).

Habitat/ecology:  "A weed of disturbed areas and cultivation" (Flora of Mozambique online).  "A weed of open ground in semi-arid regions." (Hutchison and Dalziel, 1963; p. 237).  In north Queensland Australia, several small infestations have been recorded in pasture and along roadsides in a region that experiences a monsoon tropical climate with average annual rainfall of 1600-1800 mm.

Propagation:  Achenes. A prolific seed producer.

Native range:  West Africa.

Presence:

Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Australia
Australia (continental)
Queensland introduced
Waterhouse, Barbara (year unknown)

Comments:  Recently discovered in the Mackay and Proserpine area of Queensland, Australia (Barbara Waterhouse, pers. com.).


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This page was created on 18 AUG 2000 and was last updated on 3 MAR 2013.