Homalium brachyrhachis Sleumer

Applequist, Wendy L., 2018, A revision of the Malagasy species of Homalium sect. Blackwellia (Salicaceae), Candollea 73 (2), pp. 221-244 : 229-230

3. Homalium brachyrhachis Sleumer in Bull. Jard. Bot. Natl. Belg. 43: 261. 1973.

Holotypus: MADAGASCAR. Prov. Toliara: crêtes et barres calcaires au lieu dit Ankiranja, à 30 – 35 km de Manja [21°25'S 44°20'E] sur la route de Bevoay [21°50'S 43°52'E], 3–4.XII.1969, fl., Service Forestier 28953 ( P [ P04705554 ]!; isotype: L [ L0010886 ] image seen, TEF [ TEF000288 ] image seen) .

Tree to 6 – 7 m or large shrub; bark platanoid; young twigs glabrous. Leaves elliptical to ovate, (2.7–)3.9 – 6.2 × (2–) 2.5–3.5 cm; petiole 11–16 mm; base rounded (convex), the extreme base attenuate; apex short-acuminate to acute (obtuse); margins prominently crenate-serrulate, with glands small, round, inside teeth apices; adaxial surface drying olive, abaxial surface pale green. Inflorescences racemose, lateral, 1.5 – 3.8 cm, glabrous; flowers pedicellate with pedicels 2– 3 mm; bracts not seen. Flowers 7 –8-merous; calyx tube funnelform with rounded base, minutely pubescent; sepals ligulate with acute apex, 1.5–2.5 mm; petals ligulate with acute apex, 1.8–2.5 mm; sepals and petals about equal to calyx tube or slightly longer, ascending (partly spreading to somewhat reflexed), short-ciliate, abaxial surface minutely pubescent with narrow dark stripes, adaxial surface sparsely pubescent; sepal glands pubescent; filaments 1–1.4 mm, glabrous; ovary pubescent; styles 3–4, 0.8–1.4 mm, basally pubescent.

Distribution, ecology and conservation status. – Homalium brachyrhachis is the only species of this section known from dry western forest on limestone. It is known from only two contemporaneous collections in northwestern Toliara province, on the road from Manja to Bevoay, representing a single population. No further material has been collected for almost 50 years. The natural vegetation in this region is mostly extirpated and the remnants suffer ongoing threats and anthropogenic degradation; some land in the region is protected, but the original locality is not. This species, if it still exists, may therefore be at imminent risk of extinction. An appropriate preliminary assessment of conservation status is therefore “Critically Endangered” [CR B1ab(iii)+B2ab(iii)].

Additional material examined. – MADAGASCAR. Prov. Toliara: crêtes et barres calcaires au lieu dit Ankiranja , à 30–35 km de Manja sur la route de Bevoay, 3–4.XII.1969, fl., Service Forestier 28936 ( P [4 sheets]) .