Homalium sect. Rhodonisa (Tul.) Sleumer

Applequist, Wendy L., 2016, A reconsideration of the infrageneric classification of Homalium Jacq. (Salicaceae), Candollea 71 (2), pp. 231-256 : 255

9. Homalium sect. Rhodonisa (Tul.) Sleumer

in Bull. Jard. Bot. Natl. Belg. 43: 300. 1973.

÷ Nisa [unranked] Rhodonisa Tul. in Ann. Sci. Nat., Bot. ser. 4, 8: 70. 1857 [as Rhodonisae].

Typus: Homalium sanguineum (Boivin ex Tul.) Baill. (÷ Nisa sanguinea Boivin ex Tul. ) (designated by Sleumer, 1973: 300).

Stipules axillary, free. Inflorescences spiciform to paniculate; bracts broad (sometimes rather short), bracts and bracteoles persistent. Flowers short-pedicellate, with pedicels articulated usually just below the receptacle, to subsessile or sessile; perianth (4-)5(-6)-merous. Sepals oblong, sometimes broadly or narrowly, to somewhat obovate, ovate, or elliptical (seldom to oblanceolate or lanceolate), moderately accrescent and usually curving over the fruit; calyx tube tubular with a narrowed base, often visibly ridged or grooved, to funnelform, in fruit tubular to turbinate or ellipsoid; sepal glands of moderate size, broadly elliptical to rounded (somewhat oblong or trapezoid). Petals oblanceolate to obovate, much longer than sepals, ascending (spreading), accrescent; sepals and petals ciliate, usually shortly, or not. Stamens 1 per petal, inserted between glands; anthers varying from broadly oblong-elliptical with oblong-elliptical locules, the slits of dehiscence nearly parallel, to small, broader than long with small subglobose locules, widely separated lateral slits towards apex (sometimes apparently or nearly basifixed with connective not prominent). Upper surface of ovary sometimes quite narrow, nearly flat to shallowly conical in flower, in fruit convex to conical (or little expanded in narrow-ovaried species); styles usually fused into a column (or connivent) for at least half of length (sometimes quite short), the branches 4-5. Locule of fruit narrowly cylindrical or ellipsoid (to narrowly obovoid), pubescent throughout; seeds 2-4 per fruit, small (possibly no mature seeds seen).

Distribution. – Madagascar.

Species included. – Homalium albiflorum , H. baillonii Scott- Elliot, H. leucophloeum (Tul.) Baill. , H. rubriflorum , H. sanguineum .

Notes. – The most recent treatment of Malagasy Homalium ( Sleumer, 1973) recognized only three species in sect. Rhodonisa, with Homalium leucophloeum and H. baillonii synonymized under H. albiflorum var. leucophloeum (Tul.) Baill. ex H. Perrier. Preliminary study of the H. albiflorum complex (Applequist, unpubl. data) suggests that it encompasses several distinct species and that H. leucophloeum and H. baillonii should be resurrected for two of these.