Homalium sanguineum (Boivin ex Tul.) Baill.

Applequist, Wendy L., 2020, A revision of Homalium sect. Rhodonisa (Salicaceae) endemic to Madagascar, Candollea 75 (2), pp. 245-268 : 265-266

11. Homalium sanguineum (Boivin ex Tul.) Baill.

in Bull. Mens. Soc. Linn. Paris 1: 575. 1886.

≡ Nisa sanguinea Boivin ex Tul .

in Ann. Sci. Nat., Bot. sér. 4, 8: 70–71. 1857.

Lectotypus (designated here): MADAGASCAR. Reg. Analanjirofo [Prov. Toamasina]: Ile Ste. Marie, bords de la mer un près de Tanambo [Tanambao], V.1847, fl. & fr., Boivin 1846 ( P [ P04734378 ]!; isolecto-: BM, G [ G0001388 , G0001389 ] images seen, L [ L0011012 fragment] image seen, P [ P04734379 , P04734380 and attached sheet of fragments]!, W) .

Tree to 20 m tall with main trunk to 12 m, dbh 25 cm; twigs pale gray, glabrous. Leaves broadly elliptical (elliptical, somewhat obovate), (5.6–)7.7–11.7 × (3.8–) 4.2–8.2 cm, thintextured; margin subentire; base broadly convex, at extreme base short-attenuate; apex rounded to emarginate or cuspidate; both surfaces glabrous, drying dark brown; secondary veins slightly prominent; petiole (9–) 12– 22 mm, glabrous. Inflorescences sometimes partly terminal, panicles with well-developed branches (partly reduced to racemes), (7.5–) 10–24 cm; peduncle (1–)2.3–7(–15) cm; rachis short-pubescent distally; flowers 1 per node; flowers sessile. Flowers (4)5-merous, red; sepals narrowly oblong-ovate to ovate, 1.4–2.4 mm, sparsely short-pubescent outside, margins usually short-ciliate; sepal glands irregularly broadly elliptical, 0.5–0.6 × 0.4 mm; calyx cup sparsely short-pubescent; petals oblanceolate to obovate, 4.4–6.3 mm, probably accrescent, glabrous, margins sometimes sparsely and minutely ciliate; filaments c. 1.1–1.2 mm; anthers broadly elliptical, 0.3 mm high.

Vernacular names and uses. – “Hafotrantsotry vavy” (Raharimalala 269); “Tanatanam-potsy ” (Antilahimena et al. 911, Rabehevitra 38).

“Matière végétale”, presumably leaves, are used in the making of Malagasy rum (Rabehevitra 38).

Distribution, ecology and conservation status. – Homalium sanguineum is native to low-altitude humid forests in a small portion of northeastern Madagascar. Only three distinct populations have been collected, and the species appears to be rare. The EOO is estimated as 240 km ², and the AOO as 12 km ² (the three populations are clearly separated, but are arranged in almost a linear pattern, making the calculated EOO low). One collection was made in the protected area of Mananara-Nord. However, most of the habitat is unprotected and continues to suffer anthropogenic damage.

Therefore, the estimated conservation status of this species is “Endangered” [EN B1ab(iii)+B2ab(iii)].

Notes. – The holotype of Nisa sanguinea has been reported to be at P ( SLEUMER, 1973: 301, with the collection number misstated as the year of collection). Since three sheets of the type collection are present at P and no distinction among them has been published, these are syntypes and one must be selected as lectotype. The sheet numbered P04734378 is by far the best, so is chosen here. Two un-numbered Boivin collections at P have been marked as probable or questionable type material, but their status is unclear, and the specimen said to have been cultivated outside Madagascar, in the botanical garden on the island of Bourbon, certainly is not type material.

Additional material examined. – MADAGASCAR. Reg. Analanjirofo [Prov. Toamasina]: Fkt. Rantabe , 15°42'39"S 49°37'39"E, 24.II.2002, fl., Antilahimena et al. 911 ( MO) ; rte entre Rantabe et Morafeno, 15°42'39"S 49°37'51"E, 24–25.II.2002, fl., Rabehevitra 38 ( MO, P) ; Mananara-Nord , forêt d’Antsanatribe à 3 km d’Antanambe, sur piste Ambodihazovola, 12.II.1990, fl. & fr., Raharimalala 269 ( P [3 sheets]). Reg. unknown: sine loco, s.d., fl., Boivin s.n. ( P) ; Jard. Bot. de Bourbon [cultivated], 15.IV.1847, fl., Boivin s.n. ( P).