Rhodolaena coriacea G.E. Schatz, Lowry & A.-E. Wolf, 2000

Schatz, George E., Lowry Ii, Porter P. & Wolf, Anne-Elizabeth, 2000, Endemic families of Madagascar. VI. A synoptic revision of Rhodolaena (Sarcolaenaceae), Adansonia (3) 22 (2), pp. 239-252 : 244-246

4. Rhodolaena coriacea G.E. Schatz, Lowry & A.-E. Wolf , sp. nov.

Haec species foliorum apice rotundato plerumque emarginato R. bakerianae similis, sed ab ea ramulis plerumque glabrescentibus glaucescentibus, foliis longioribus plus coriaceis majore fere semper in longitudine 7 cm excedente (versus 6 cm non excedens in R. bakeriana ) atque florium majorum sepalis (2-) 2.5-3.5 cm longis (versus 1.8 cm non excedens) distinguitur.

TYPUS. — Service Forestier 25521, Madagascar, Lendava, Ampasimadinika II , canton et district d’Anosibe An’Ala, [19º30’S, 48º12’E], 15 Feb. 1965, fl. (holo-, P!; iso-, MO!, P!, TEF!) .

Small to large tree, 5-25 m tall, twigs often initially with very fine, dense, short indument, usually eventually glabrescent and sometimes glaucescent. Leaves with petiole 0.7-1.3 cm long, lamina strongly coriaceous, glabrous, elliptic, (4-)6.2-14.5 × 3.3-7.3 cm, base acute to rounded, apex rounded to emarginate, venation weakly brochidodromous with 9-12 secondary veins per side, midvein usually deeply sunken above, prominently raised below, venation usually obscure on the upper surface or sometimes the secondary veins evident, tertiary venation densely reticulate and slightly raised below, margin sometimes slightly revolute. Inflorescence solitary, axillary, 2-flowered, peduncle 2-5 cm long, glabrous except sparsely golden pubescent at apex just below involucre, involucre slightly lobed at anthesis, with dense tufts of trichomes; pedicel 0.3-0.5 cm long, 0.2 cm in diam.; outer 2 sepals elliptic, 0.4-0.5 × 0.2-0.3 cm; inner 3 sepals asymmetrically ovate, (2-)2.5-3.5 × 1- 3.8 cm, glabrous and shiny, coriaceous, persistent and becoming somewhat woody in young fruit; petals elliptic, 5-6.5 × 1.8-2.8 cm, thin membranous drying hyaline with evident venation, glabrous, base cuneate and abruptly truncate, apex obtuse to rounded; stamens ca. 30, inserted above disc at base of ovary, filaments 3-4 cm long, anthers versatile, 0.8-1 × 0.5 mm; style 3.7-4.2 cm long, stigma capitate, papillatetuberculate. Fruit 3-valved, valves broadly ovate, 1.6-1.9 cm long, 1.3-1.4 cm broad, surrounded by the accrescent, fleshy, shallowly 3-lobed involucre.— Fig. 2 .

Rhodolaena coriacea is a small to large tree that occurs in humid to subhumid forest from sea level to 1700 m elevation from Kianjavato to Anjanaharibe-Sud RS ( Fig. 3 ). This species can be difficult to distinguish from R. bakeriana , with which it shares leaves with a rounded and emarginate apex, but differs by its generally larger leaves, the largest blade on a specimen usually at least 7 cm long versus in R. bakeriana rarely exceeding 6 cm. Flowers of R. coriacea are also larger, with sepals (2-) 2.5-3.5 cm long versus sepals that do not exceed 1.8 cm long in R. bakeriana . Rhodolaena coriacea has recently been collected at both Betampona RNI and Zahamena PN/RNI.

VERNACULAR NAMES.— Arina, Harinavavy, Pikazana, Tamanampotsy, Tsimahamasatsokina, Tsimamasasokina, Vazanomby.

PARATYPES. — MADAGASCAR, Prov. Antsiranana: Rasoavimbahoaka 674, Marojejy PN , 14º27’30”S, 49º34’54”E, 920-1040 m, 15-29 May 1995, fl. ( K, MO, P, TAN); Ravelonarivo 608, Anjanaharibe-Sud RS , 14º43’10”S, 49º27’12”E, 1700 m, 14 Feb. 1995, fl. ( K, MO, P, TAN) . Prov. Fianarantsoa: Bosser 18885, Kianjavato , route de Mananjary , [21º22’S, 47º52’E], Jan. 1964, ster. ( TAN) ; Service Forestier 14735, Sahakorihina, Ambodilafa , Nosy-Varika , [20º31’S, 48º00’E, 450 m], 12 Jul. 1954, fl. ( P, TEF) . Prov. Toamasina: Andrianjafy 88, 89, Betampona RNI , 17°55’50”S, 49°12’12”E, 550 m, 19 July 2000, fr. ( K, P, MO, TAN, TEF) ; Carlson 419, Betampona RNI , 17º53’S, 49º13’30”E, 520 m, 22 Aug. 1990, ster. ( MO, TAN) ; Cours 2422 (= Herb. Inst. Sci. Madag. 2422), Dist. Tamatave, de Sahalampy à Ampitamanoka , [17º48’S, 48º51’E], 1200 m, 18 Jan. 1945, fl. ( P, TAN) , 2812, Zahamena RNI, [17º30’S, 48º38’E], 8 Mar. 1951, ster. ( TEF) ; Raharimalala 241, Mananara Biosphere Reserve, Mahavoha , [16°23’S, 49°43’30”E], 12 Feb. 1990, fl. ( P) , 370, Mananara-Nord PN, forêt d’Ambodihazovola , [16°29’S, 49°48’30”E], 26 Feb. 1990, ster. ( P) ; Ratovoson 257, Zahamena PN , 17°30’15”S, 48°43’56”E, 996-1250 m, 18 July 2000, fl. ( MO, P, TAN, TEF) ; Réserves Naturelles 2812, Zahamena RNI, [17º38’S, 48º50’E], 8 Mar. 1951, fl. ( P) ; Service Forestier 8800, entre col d’Ambatondradama et le Beanjada , [15º16’S, 50º04’E, 700-800 m], Dec. 1953, bud, fl. ( P, TEF) , 8864, crête au N du col d’Ambatondradama, [15º17’S, 50º01’E], 800 m, Jan. 1954, fl. ( P, TEF) , 8893, entre Rantabe et Tenina , [15º44’S, 49º39’E, 10 m], Jan. 1954, fl. ( P, TEF) , 9099, bassin de la Manonga (affluent rive gauche de la Rantabe ) aux environs de Sahajinja, [15º38’S, 49º25’E], 800 m, 4 Mar. 1954, fl. ( P) , 10763, Sahamamy, Anivorano , Brickaville , [18°33’S, 48°58’E, 200 m], 29 Sep. 1954, fl. ( P) , 18174, Forêt d’Analatsara, à l’Ouest de Rantolava (NW de Tampolo-Fénérive ), [17º15’S, 49º20’E], 1 Sep. 1957, fl. ( P, TEF) , 26073, Vadivohitra, près de Foravohitra , canton d’Anosibe , [19º23’S, 48º14’E], 900 m, 27 Mar. 1966, ster. ( TEF) .

Figures

Fig. 2. — Rhodolaena coriacea: A, flowering branch; B, leaf (adaxial surface); C, leaf (abaxial surface); D, flower (schematic view); E, sepals (inner, outer). — Rhodolaena macrocarpa: F, fruiting branch; G, leaf (adaxial surface); H, leaf (abaxial surface); J, dehisced fruit with involucre (A, Service Forestier 8893; B-E, Service Forestier 8864; F, Andrianjafy et al. 61; G-J, Service Forestier 27200).

Fig. 3. — Distribution of Rhodolaena coriacea, mapped on the bioclimatic zones of Madagascar (after CORNET 1974; see SCHATZ 2000).