Homalium myrtifolium Sleumer

Applequist, Wendy L., 2018, A revision of the Malagasy species of Homalium sect. Blackwellia (Salicaceae), Candollea 73 (2), pp. 221-244 : 238-239

11. Homalium myrtifolium Sleumer in Bull. Jard. Bot. Natl. Belg. 43: 258. 1973.

Holotypus: MADAGASCAR. Prov. Toamasina: Vavatenina , Fénérive-Est , 20.I.1957, fl., Réserves Naturelles 8879 ( P [ P00375094 ]!; isotype: P [ P04679966 ]!; L image seen, TAN image seen) .

Tree or shrub to 9 m; young twigs minutely pubescent when very young, soon becoming glabrous. Leaves obovate, 0.9–2.5(–3) × 0.4–1.1(–1.5) cm; petiole (0–) 0.5–2.5 mm; base cuneate to convex; apex rounded; margins few-toothed near apex to subentire, with glands small, rounded, sunk in margins at tooth apices; adaxial surface drying pale brown, abaxial surface greenish; secondary veins strongly ascending, at a narrow angle to midrib. Inflorescences racemose, lateral, 1.4–5 cm, short erectpubescent; flowers pedicellate with pedicels 0.5–2 mm (subsessile); bracts linear to lanceolate, 0.5–1 mm. Flowers 6-merous; calyx tube funnelform to subcylindrical with rounded base, pubescent; sepals ligulate to narrowly oblanceolate with acute apex, 1.4–2.6 mm; petals spatulate or ligulate to narrowly lanceolate with acute apex, 1.7–3 mm; sepals and petals greenish to yellowish white to partly pink or red (perhaps only postanthesis), modestly accrescent, usually much longer than calyx tube (especially in fruit), ascending or partly spreading, seldom becoming reflexed, ciliate, adaxial surface sparsely pubescent, abaxial surface sometimes bearing few long hairs; sepal glands long-pubescent, often rather sparsely; filaments 1.6–2.5 mm, sparsely pilose; ovary pilose to hispid (becoming glabrate); styles 3(4), 1.3–1.7 mm, basally pilose.

Vernacular name. – “Hazombato” (Réserves Naturelles 8879).

Distribution, ecology and conservation status. – Homalium myrtifolium is native to low- to mid-altitude humid forests in Toamasina and Toliara. Only three distinct locations have been documented. All collections from Toliara come from the area of Tsitongambarika, which is protected, and the species has been collected once near, though not within, Zahamena National Park. The third population, from an unprotected area, has not been recollected since 1957. Though the Area of Occupancy is estimated at only 16 km ², the Extent of Occurrence is estimated at c. 12,600 km ². However, much of the intervening habitat is unsuitable due to ongoing anthropogenic damage. Although the fact that the only apparently thriving population is protected argues against a conservation status of Endangered, the species should be considered “Near Threatened” [NT] based on its limited range and the uncertain status of one of the formerly existing populations.

Notes. – Homalium myrtifolium is easily recognized by its small, pale-drying obovate leaves with entire or minutely toothed margins and few, ascending secondary veins. It is the only species that has secondary veins ascending at a narrow angle to the midrib; it is among the group with racemose inflorescences and pubescent sepal glands.

Most collections come from a single small region in southeastern Toliara; two collections come from Toamasina, well to the north. The morphology of those collections is not significantly different from that of the southern collections.

Additional material examined. – MADAGASCAR. Prov. Toamasina: A l’W du village d’Ambatoaranana , NE de la RNI de Zahamena , 17°33'30"S 48°53'20"E, 900 m, 24.I.1994, fr., Randrianjanaka & Be Maxime 52 ( MO, P) . Prov. Toliara: Fkt. Antsotso , forêt d’Ivohibe , 24°34'15"S 47°12'36"E, 44 m, 29.I.2015, fl., Randriatsivery et al. 580 ( G, MO); Antsotso Avaratra , 24°33'54"S 47°11'55"E, 432 m, 11.XII.2007, fl., Razakamalala et al. 3882 ( MO, P [2 sheets]); Antsotso Avaratra, forêt Tsitongambarika , 24°34'16"S 47°12'05"E, 271 m, 1.IV.2008, fl., Razakamalala et al. 4108 ( MO, P); Fkt. Antsotso, forêt d’Ivohibe , 24°33'51"S 47°12'20"E, 395 m, 28.I.2015, fl., Razanatsima et al. 1385 ( G, MO); forêt de Bemangidy , au N de Mahatalaky , Fort-Dauphin , 1–2.II.1963, fl., Service Forestier 22339 ( P); Bemangidy Forest , 24°34'15"S 47°12'36"E, 150 m, 13.IV.2010, Thulin & Razafindraibe 11855 ( MO) .