244. Chromolaena Candolle, Prodr. 5: 133. 1836.
飞机草属 fei ji cao shu
Osmia Schultz Bipontinus.
Subshrubs, shrubs, or perennial herbs, erect to somewhat scandent. Leaves usually opposite; blade mostly ovate or triangular to elliptic, sometimes linear, subentire to lobed. Synflorescences usually thyrsoid to candelabriform or with lax to densely corymbose branches, rarely of solitary capitula on long erect peduncles. Phyllaries 18-65, 4-6-seriate, markedly unequal, gradate, often with expanded herbaceous or colored tips; receptacle flat to slightly convex, glabrous, sometimes paleaceous. Florets 6-75; corollas white, blue, lavender, or purple, rather cylindric with scarcely narrower base, outer surface smooth below lobes, with few to many shortly stalked glands, often with rather stiff hairs; lobes slightly to distinctly longer than wide; usually densely papillose on inner surface, or smooth (Chromolaena subg. Osmiella R. M. King & H. Robinson); antheropodia usually broader below, narrowed apically, or not broadened below (C. subg. Osmiella); anther appendages large, oblong, ca. 1.5 × as long as wide, entire or crenulate at tip; style base not enlarged; style branches narrowly linear to slightly broadened distally, slightly mammillate to densely long papillose. Achenes prismatic, (3-)5-ribbed, with setulae mostly on ribs; carpopodium distinct, broadly cylindric or narrowed below; pappus setae ca. 40, slender, persistent, not or scarcely broadened distally. x = 10, 16.
About 165 species: New World tropics and subtropics, one species a pantropical weed; one species (introduced) in China.
King and Robinson (Monogr. Syst. Bot. 22: 1-581. 1987) noted two subgenera and provided characters in their generic description to separate species of Chromolaena subg. Osmiella. Concern is growing in many tropical countries over the alarming spread of the weed Chromolaena odorata (e.g., C. Zachariades et al., Proc. 5th Int. Workshop Biol. Control Managem. Chromolaena odorata. 2002). The taxonomy and distribution of this species has been well documented by L. Gautier (Candollea 47: 645-662. 1992).