Taxonomy

Mikania micrantha Kunth., Nov. Gen. Sp. [H.B.K.] 4(15): 105 (ed. fol.). 1818.

Common synonyms

Willoughbya micrantha Rusby Mem. Torrey Bot. Club 4: 211. 1895.

Common name

Bitter vine, American rope, Chinese creeper, climbing hempweed, Mikania, mile-a-minute weed

Description

Propagule or dispersal unit is the fruit with pappus. Fertile part 1.3-2 mm long, 0.3-0.5 mm wide, in side view mostly +/- equal thickness (cylindrical) or widest in upper part (obovoid), +/- straight, the upper (apical) end suddenly cut off (truncate), in cross-section angular (prismatic), basal scar (carpopodium) pronounced and well-differentiated, central, beak (=thinner sterile stalk between seed and pappus) absent, wings absent, fruit surface black, smooth (except at cellular level), with glands or glandular hairs, thickened margin absent, longitudinal ribs present, (4-)5, their surfaces smooth, with no hairs (glabrous) or simple straight hairs.

Pappus type bristles / hairs, pappus elements all +/- similar, up to 2-4 mm long, in one row, pappus elements numerous, persistent, the individual bristles rough / serrated (barbellate), +/- equal width along length, white / translucent or brown.

Notes: Very similar to Mikania cordata but with the fertile part of the fruit shorter than 2 mm. The pappus is initially white but becomes brown with age. The fruit surface looks bumpy but only at the level of the cell structure, so it is scored as smooth.

Ecology

Perennial climber (vine) with potential to cover and suffocate native vegetation, fruits wind-dispersed. Tropical; needs moisture and cleared, open or disturbed areas, but flexible with regard to substrate. Found especially in agricultural lands, managed forests, along roads, and in urban areas.

Native range

Central America, South America.

Introduced range

Widespread across South Asia and Southeast Asia from India to Indonesia, tropical Australia, and the Pacific.

Weed status within Australia

Tropical Weed under National Eradication; NAQS target species; NSW: Class 1 State Prohibited Weed; Qld Restricted Invasive Plant Cat. 2-5; NT Category C; WA Declared Pest s12 (C1 Prohibited).

Past interceptions (Australia): origins

Turkey, Thailand.

Other or unidentified species of the genus also from Papua New Guinea, Fiji.

Past interceptions (Australia): commodities

New vehicles.