Koyamasia H.Rob., Proc. Biol. Soc. Washington 112(1): 234. 1999.

Bunwong, Sukhonthip, Chantaranothai, Pranom & Keeley, Sterling C., 2014, Revisions and key to the Vernonieae (Compositae) of Thailand, PhytoKeys 37, pp. 25-101 : 75

Koyamasia H.Rob., Proc. Biol. Soc. Washington 112(1): 234. 1999.

Type.

Camchaya calcarea Kitam., Acta Phytotax. Geobot. 23: 71. 1968.

Description.

Perennial herbs. Stems erect, pubescent. Leaves simple, alternate, petiolate, lamina ovate or elliptic, margin serrate, apex acute or acuminate, base attenuate. Capitulescences terminal, solitary or paniculate. Capitula discoid, homogamous; pedunculate, florets bisexual and fertile. Involucre imbricate, phyllary tips recurved. Florets 60-100; corollas purplish or white, actinomorphic; corolla lobes 5. Anthers 5, syngenesious. Styles 2-branched, inner surface covered with stigmatic papillae, outer surface covered with sweeping hairs reaching to below style bifurcation. Achenes subterete, 10-ribbed, carpopodium absent. Pappus in one series of bristles, deciduous. Pollen echinolophate, 3-porate, without micropuncta.

Three species are recognized in Thailand.

Key to the species

1	Capitula broadly campanulate, 15-30 mm long, involucres hemispherical, 15-20 mm long, 15-20 mm in diam., florets ca. 100	Koyamasia calcarea
-	Capitula campanulate, 15-20 mm long, involucres campanulate, 7-10 mm long, 8-15 mm in diam., florets ca. 60	Koyamasia curtisii