Mikania micrantha Kunth
Family Asteraceae, Tribe Eupatorieae
Fruit an achene, narrowly oblanceolate to narrowly oblong, sometimes slightly curved, 1.2–2(3) mm long, 0.2–0.6 mm in diameter, with 4–5 light-colored longitudinal ribs; cross section 4 or 5 sided. Surface blackish-brown, minutely granular, with few to many conspicuous drops of amber resin. Base narrows, then flares into a straw colored, irregularly cup shaped basal scar. Pappus persistent, one row of 32–38 ivory to light amber finely barbed bristles, 2–3 mm long. Style base inconspicuous. Apex horizontal, blackish-brown, granular. Embryo straight, spatulate; endosperm absent.
Ageratina adenophora (Sprengel) R. King & H. Robinson (=Eupatorium adenophorum Sprengel)
Ageratina riparia (Regel) R. King & H. Robinson
Mikania cordata (Burm. f.) Robinson
Mikania scandens (L.) Willd. (non-FNW)
native to Central and South America, Mexico, and the West Indies
naturalized in India, Pakistan, Sri Lanka, Southeast Asia, the Pacific Islands, United States
wet places, sometimes at high elevations, forest borders and clearings, along streams and rivers; a weed of pastures, tree crops, open disturbed areas, roadsides, waste places
Mikania micrantha is a rapidly growing herbaceous to semi-woody, perennial vine. It grows quickly over other plants such as young trees, smothering them; it can climb trees up to 25 m tall. Although not as serious a weed as M. cordata, in Southeast Asia it has become a hard-to-eradicate weed of tea, rubber, and other plantation crops. It also reduces the carrying capacity of pasture. The achenes are spread by wind, water and animals. The plant also reproduces by old rootstocks, runners, and suckers.