36. Trichodesma R. Brown, Prodr. 496. 1810.
毛束草属 mao shu cao shu
Subshrubs or perennial herbs, minutely hispid or glabrous. Leaves opposite or alternate, entire. Cymes terminal, becoming racemelike or paniculate, bracteate. Calyx 5-parted, becoming fastigiate or ovoid, base 5-veined or winged; lobes oblong to lanceolate, enlarged in fruit. Corolla broadly tubular, frequently tomentose inside; throat appendages usually absent; limb 5-parted; lobes triangular-ovate, apex caudate-attenuate. Stamens inserted on lower part of corolla tube; anthers oblong-linear to lanceolate, with awnlike and spiral-twisted connectives at apex. Ovary 4-parted. Style linear, exserted from corolla throat; stigma obscure. Gynobase fastigiate and 4-veined longitudinally. Nutlets dorsiventrally compressed, margin of abaxial surface protruding, becoming cupular, dentate. Seeds suborbicular.
About 40 species: Africa, tropical Asia, Australia; one species in China.
The genus Lacaitaea was created by Brand for Trichodesma calycosum, the only species of Trichodesma with appendages in the throat. The unusual number of 10 appendages is due to the partition of each scale by a vein running down from the corolla lobe. It is difficult to understand why this species alone possesses a peculiarity of usually considerable taxonomic importance, as already pointed out by Johnston (J. Arnold Arbor. 33: 75. 1952). The species is retained in Trichodesma because it is very similar to other species of Trichodesma in all other characters.