Homalium baillonii Scott-Elliot

Applequist, Wendy L., 2020, A revision of Homalium sect. Rhodonisa (Salicaceae) endemic to Madagascar, Candollea 75 (2), pp. 245-268 : 251-252

3. Homalium baillonii Scott-Elliot in J. Linn. Soc., Bot. 29: 23. 1891.

Holotypus: MADAGASCAR. Reg. Anosy [Prov. Toliara]: Fort Dauphin, VI.s.a., fl., Scott Elliot 2853 ( K [ K000231483 ] image seen; iso-: BM, P [ P04679196 ]!).

Tree to 12(–20) m or shrub; twigs pale, grayish (dark brown), glabrous. Leaves broadly elliptical to elliptical, (5.3–)6.2–12(– 15) × (2.8–) 3.5–8.5 cm, fairly thick-textured; margin subentire to very shallowly repand; base broadly convex (rounded, often minutely attenuate at extreme base); apex cuspidate (partly obtuse, rounded, or emarginate); both surfaces glabrous, drying greenish or brownish, the adaxial surface usually darker (to blackened); secondary veins little prominent; petiole sometimes red, (10–)14–28(–33) mm, glabrous. Inflorescences racemose, (2.5–) 5–15 cm; peduncle 0.1–0.6(–1.2) cm; rachis glabrous; flowers (1)2 –3(4) per node; pedicels 0.5 – 1 mm, sparsely pubescent to glabrate, or flowers sessile. Flowers 4-merous, whitish (pinkish white); sepals oblong to broadly oblong (slightly obovate), 1.8–2.6 mm, glabrous except margins sparsely short-ciliate; sepal glands broadly oblong or elliptical to orbicular, 0.5–0.7 × 0.4–0.5 mm; calyx cup glabrous (sparsely short-pubescent); petals narrowly obovate, 4–8.5(–10.3) mm, accrescent, glabrous, margins not ciliate; filaments 0.9–1.3 mm; anthers broadly elliptical (or transversely elliptical?), 0.3 mm high.

Vernacular names and uses. – “Hazoala” (Randrianaivo et al. 2364); “Lalampito” (Service Forestier 7775); “Lampivahatry” (Randrianaivo et al. 2364); “Lapivahatra” (Ramison & Armand 313); “Lohariana” (Réserves Naturelles 3813); “Menaky” (Ludovic 1584); “Takonandro” (Service Forestier 1553, 5324); “Tapinandro” (Ludovic 1697,1763); “Tsihanimposa” (Ratovoson 1901); “Tsitakonandro” (Service Forestier 7775); “Tsivalandra” (Réserves Naturelles 7471); “Tsivalandravy” (Réserves Naturelles 7470); “Voankazonala” (Randriantafika 61).

Wood is used for domestic heating (Ludovic 1584, 1763) and trunks are used for construction of traditional houses (andavany; Ludovic 1697, 1744, 1763) and planks used to make household furnishings (Ludovic 1763).

Distribution, ecology and conservation status. – Homalium baillonii is endemic to southeastern Madagascar ( Fig. 2 ). It occurs in littoral forest or low-altitude humid forest, on sand. Its habitat includes the protected areas of Mandena, Ste. Luce, and Andohahela.

The EOO is estimated as 10,895 km ², and the AOO as 64 km ². However, the large majority of accurately located collections occur in a very small area, and it is not evident that more than ten distinct populations exist. Because the unprotected portions of the habitat are suffering ongoing anthropogenic degradation and loss, a preliminary estimate of the species’ conservation status is “Vulnerable” [B1ab(iii)+B2ab(iii)]. The species was collected outside the Anosy region once in 1954 and never again since then, despite repeated botanical collections in remaining low-altitude and coastal forests. If that population were excluded as probably extinct, the EOO would be estimated as 1403 km ² and the AOO as 60 km ².

Notes. – Homalium baillonii , which was lumped by SLEUMER (1973) into H. albiflorum , is herein reinstated as a distinct species. It is distinguished by many characters, including its thick-textured leaves often with subentire margins and proportionally long petioles; short-peduncled, glabrous inflorescences; flowers tetramerous and very short-pedicellate or sessile; and glabrous sepals and petals (except for ciliate sepal margins). Additionally, it is native to southeastern Madagascar and has clearly different ecological preferences ( Fig. 2 ). It is much more similar to H. leucophloeum , also herein removed from H. albiflorum , which almost always has sessile flowers and has proportionately narrower and on average somewhat shorter leaves, which usually have shorter petioles than those of H. baillonii and slightly more prominent veins. That species occurs farther north than H. baillonii , and at least usually at higher elevations.

Additional material examined. – MADAGASCAR. Reg. Anosy [Prov. Toliara]: Fort Dauphin, VII.1890, fl., Catat 4317 ( P) ; Fort-Dauphin, 28.VI.1926, fl., Decary 4182 ( P) ; Fort-Dauphin, 1.VII.1926, fl., Decary 4245 ( P) ; Pointe Itaperina , distr. de Fort-Dauphin, 13.VII.1932, fl., Decary 10126 ( P) ; Mandena, 24°57'S 47°00'E, 0–10 m, 17.IV.1989, fr., Dumetz et al. 684 ( P) ; Mandena, 24°57'S 47°00'E, 0–10 m, 25.X.1989, fr., Dumetz et al. 790 ( MO, P) ; Andohahela RNI , près du village Taviala-Andohavondro , 24°59'S 46°43'E, 175–200 m, 28.VI.1995, fl., Eboroke & Paul 1042 ( G, MO, P) ; N side of Antorendrika River 22 km NE Tôlanaro, 0–20 m, 22.III.1989, fr., Gereau et al. 3308 ( MO, P) ; Entre le pic St Louis et la mer, 1–5 m, 20.IX–6.X.1928, fr., Humbert 5985 ( P) ; forêt de Fasimalandy , 24°42'41"S 47°11'18"E, 15 m, 31.VIII.2012, fl., Ludovic 1567 ( MO) ; forêt d’Ampasipotsy , 24°43'03"S 47 °11'09"E, 17 m, 3.IX.2012, ster., Ludovic 1584 ( MO) ; forêt d’Angiritso , 24°49'36"S 47 °08'37"E, 26 m, 10.IX.2012, fr., Ludovic 1697 ( MO) ; forêt d’Ankatafamamy , 24°54'17"S 47°07'01"E, 20 m, 14.IX.2012, fr., Ludovic 1744 ( MO) ; forêt d’Ambatomena , 24°49'36"S 47°08'37 "E, 26 m, 16.IX.2012, fr., Ludovic 1763 ( MO) ; Ste. Luce , 24°46'S 47°09'E, 10 m, 20.X.1989, fl., Rabevohitra 2056 ( MO, P) ; Mahatalaky, 24°50'19"S 47°08'14"E, 6 m, 8.VIII.2012, fl., Rakotonirina et al. 881 ( MO) ; Sainte Luce, Malailay be , 24°50'09"S 47°08'12"E, 6 m, 7.VIII.2012, fl., Ramananjanahary et al. 686 ( MO) ; Mandromondromotra, Site IV, 24°55'22"S 47°01'30"E, 62 m, 18.VI.1997, fl. & fr., Ramison & Armand 313 ( MO) ; Ampasy Nahampoana, forêt Omega , 24°57'52"S 47°00'13"E, 22 m, 24.VIII.2013, fr., Randrianaivo et al. 2364 ( G, MO) ; Mandena, 24°57'08"S 47°00'11"E, 96 m, 12.VI.1999, fl., Randriatafika 61 ( MO, P) ; Tapatany, 3 km E de Belavenoka , 24°52'21"S 47°07'21"E, 50 m, 4.VIII.2012, fl., Ratovoson 1901 ( MO) ; Mandena , 24°57'S 47°00'E, 0 m, 22.VI.1996, fl., Razafimandimbison 220 ( G, K, MO, P) ; Mahatalaky, Belavenoky , 24°51'29"S 47°07'12"E, 27 m, 9.VIII.2012, Razakamalala et al. 6914 ( MO) ; Andohahela, Ifarantsa , 21.IV.1952, fl., Réserves Naturelles 3813 ( P [2 sheets]) ; Ifarantsa, 26.V.1955, fl., Réserves Naturelles 7470 ( P) ; Fenoro, Ifarantsa , 28.IV.1954, fl., Réserves Naturelles 7471 ( P) ; Enaniliha , Fort-Dauphin, 8.I.1956, fl., Réserves Naturelles 8537 ( P) ; forêt de Mandena , 17.IX.1950, fl., Service Forestier 1553 ( P) ; ibid. loco, 12.VI.1952, fl., Service Forestier 5324 ( P) ; ibid. loco, VIII.1953, fl., Service Forestier 7775 ( P) ; ibid. loco, 24°57'S 47°02'E, 10 m, 22.V.1991, fl., Zarucchi et al. 7446 ( MO, P). Reg. Vatovavy-Fitovinany [Prov. Fianarantsoa]: Ambodiramiavona, Mananjary , 17.VI.1954, fr., Service Forestier 14717 ( P).

Figures

Fig. 2. – Map of representative distributions of species in the Homalium albiflorum complex, approximated as necessary.