Octolepis dioica Capuron

Rogers, Zachary S., 2005, A revision of Octolepis Oliv. (Thymelaeaceae, Octolepidoideae), Adansonia (3) 27 (1), pp. 89-111 : 101-103

3. Octolepis dioica Capuron

Adansonia, n.s. 3: 138 (1963). — Type: Service Forestier (Capuron) 18002, Madagascar, Prov. Antananarivo, forêt Ambohitantely, sur le Tampoketsa d’Ankazobe, c. 1600 m, [18°09’S, 47°18’E], June 1957, ♀ fl. (holo-, P!; iso-, G!, K!, MO!, TEF!) .

Octolepis dioica Capuron f. macrocarpa Capuron, Adansonia , n.s. 3: 140 (1963). — Type: Service Forestier (Ravelojaona) 6028, Madagascar, Prov. Antananarivo, région de Tsinjoarivo (Ambatolampy), [1500 m], [19°38’10”S, 47°41’30”E], 27 Oct. 1952, fr. (holo-, P!; iso-, TEF!); syn. nov.

Trees to 20 m tall; young stems strigosetomentose. Leaves alternate or subopposite; blades broadly obovate or elliptic, rarely suborbicular, 2.0-6.0(-6.5) × 1.4-4.0 cm, length/ width ratio c. 1.5-2.5:1, coriaceous, surfaces usually discolorous, adaxial surface glabrous, abaxial surface lighter green-brown, sparsely strigose or glabrescent, apex slightly emarginate to retuse, rarely acute, rounded or rarely short cuspidate, margin strigose or glabrescent, revolute, more so near base, base short attenuate or cuneate; midrib strigose or glabrescent; venation strongly raised to nearly inconspicuous on both surfaces, secondary veins c. 5-7 pairs, straight or slightly arched towards apex, angle of divergence from midrib 45-65°, submarginal vein loop c. 1-3 mm from margin; petioles 4-7 mm long, c. 1 mm in diam., strigose-tomentose or glabrescent. Inflorescences axillary, usually borne on defoliated portion of stem; fascicles 3-7-flowered, 1 or 2 flowers persistent; pedicels 4-10(-14) mm long, c. 0.5 mm in diam., glabrescent or sparsely strigose. Flower buds 2-3.5 × 2.5-3.5 mm, glabrescent, rarely sparsely strigose, ± smooth. Flowers 8-11 mm wide; sepals 4-5(6), ovate or oblong, rarely suborbicular or subtriangular, 4-7(-10) × 2-4 mm, coriaceous, glabrescent on both surfaces, apex acute or rounded, tomentose, margins glabrescent or tomentose; petals 4-5(6), densely to moderately strigose, rarely glabrescent near base; each petal lobe narrowly triangular, (3.5-)4.5-6.5(-8.0) × 0.5-1.2 mm, length/width ratio c. 5-7:1, coriaceous, apex acute. Staminate flowers with spreading sepals; stamens 10; filaments 2.5-4.7 × 0.2-0.3 mm; anthers 1.5-2.4 × 0.8-1.3 mm; pistillode minute, obscured by dense erect receptacle trichomes, trichomes 0.5-1.0 mm long. Pistillate flowers with erect sepals; staminodes 10, 0.5- 1.2 mm long, 0.1-0.3 mm wide (at base), smooth or rugulose, glabrous; rudimentary anthers globose or undifferentiated; ovary 1.8- 3.4 × 1.8-2.4 mm, surrounded by many erect receptacle trichomes, trichomes 0.7-0.9 mm long; style 0.0-1.1 × 0.4-0.5 mm, glabrescent. Fruits ovoid-pyramidal, 1.9-3.0 × 1.6-2.3 cm; dehiscence lines 4 or 5 (i.e. 4 or 5 carpels develop), usually strongly depressed, bicarinate on both sides of line; pericarp fleshy, c. 4-6 mm thick, rugose or rugulose, sparsely or moderately covered with short indument, trichomes c. 1.0- 1.5 mm long, subadpressed or erect; persistent style to 2 mm long. Seeds dark brown or black, 1.3-1.9 cm long, 5-7 mm wide, puberulent.

Refer to CAPURON (1963: 139, pl. 2, Nos 1- 10) for an illustration of O. dioica .

DISTRIBUTION AND PHENOLOGY. — Octolepis dioica occurs in humid forests along the central plateau of Madagascar from c. 850-1650 m elevation ( Fig. 8). It has been collected as far north as Marojejy National Park, and as far south as Andohahela National Park (Parcel 1). The species flowers from February to December and fruits from September to February. Flowering time may be no more than one or two weeks in length based on my observations of the population growing at Ranomafana National Park. Flowers and fruits do not occur on the same plant simultaneously.

V E R N AC U L A R N A M E S. — Avoha (Ser vice Forestier 17898); Gavoala (Service Forestier 34058); Fanamoratrakoho (Service Forestier 17898); Fanamosatrakora (Service Forestier 34480); Hafotramaladia (Service Forestier s.n. [20 Dec. 1951]); Havoa (Service Forestier 48-R- 121, Service Forestier 6028); Valolahy (Service Forestier 16804, 16824, 18001, 18002).

CONSERVATION STATUS. — Octolepis dioica is relatively widespread in Madagascar and occurs in several protected areas: Ambohitantely Special Reserve, Andohahela National Park, Marojejy National Park, Ranomafana National Park, Zahamena National Park. The extent of occurrence of the species is c. 90000 km 2 and the area of occupancy is c. 80000 km 2 based on a 100 km grid cell size (cell width/height, not area). At the present time, O. dioica should be considered a species of Least Concern (LC), but its status may need to be upgraded in the future, as suitable habitat continues to disappear in the high plateau region of Madagascar.

TYPIFICATION. — Two collections of Octolepis dioica were made from Ambohitantely Special Reserve by René CAPURON in June 1957, one was staminate (Service Forestier 18001), while the other was pistillate (Service Forestier 18002). Specimens of both collections are deposited at P and are annotated with the word “Type” in CAPURON’ s handwriting, but only the latter was designated as the type in the original publication, so it is thus to be regarded as the holotype. SF 18001 is a paratype.

Octolepis dioica is distinguished from O. ibityensis , the most morphologically similar species, by a number of vegetative, floral, and fruit characters ( Table 2). Octolepis dioica differs from O. oblanceolata , a species previously described as a form of O. dioica , by its shorter leaves (longest leaf blades 2.8-6.0(-6.5) vs (7.0-) 7.4-12.4 cm long) with flat (vs undulate) margins and by its smaller flowers (8-11 vs 11-13 mm wide).

CAPURON (1963) based Octolepis dioica f. macrocarpa on a single collection (Service Forestier 6028), which had smaller leaves and larger fruits with more pronounced carinate dehiscence lines than the other specimens available to him at the time of description. I observed overlapping variation in these characters at Analamazoatra Special Reserve and Ranomafana National Park, which suggests that the variation in fruit morphology noted by CAPURON is most likely due to differences in maturity and the number of developed seeds.

Three collections are excluded from the description of Octolepis dioica (Andrianjafy 209, Service Forestier 28811, 28813). Both Service Forestier col- lections, determined as O. dioica by CAPURON, were made in 1969 from Kalalao forest, a small degraded forest on laterite on Île Ste Marie. Andrianjafy 209 was recently collected at 600 m elevation in Zahamena National Park. All three collections have leaves similar to those found in O. dioica , but differ by their densely sericeous pedicels and sepals.

ADDITIONAL MATERIAL EXAMINED. — MADAGAS- CAR: Service Forestier s.n. without precise locality, st. (TEF!). — Prov. Antananarivo: Rogers et al. 118, Ambohitantely Special Reserve , 2 km NE of the park entrance, dense humid forest on laterite, 1600 m, 18°10’08”S, 47°16’40”E, 6 Feb. 2003, st. (MO); Rogers et al. 119, same locality, st. (MO!); Rogers et al. 123, same locality, st. (MO!); Rogers et al. 125, same locality, st. (MO!); Service Forestier (Ravelojaona) 48- R-121, Tsinjoarivo, (Ambatolampy), [1500 m], [19°37’30”S, 47°41’30”E], 20 July 1951, st. (TEF!); Service Forestier ( Ecol. Forest .) 16804, Manankazo- Ankazobe SF, village le plus proche Poste Forestier Manankazo, [1300-1600 m], [18 °09’00” S, 47°14’00”E], 22 June 1955, y.fl. (TEF!); Service Forestier ( Ecol. Forest .) 16824, same locality, 22 June 1955, y.fl. (P!, TEF[2]!); Service Forestier (Capuron) 18001, Forêt d’Ambohitantely, sur le tampoketsa d’Ankazobe, c. 1600 m, [18°09’30”S, 47°18’E], June 1957, ³ fl. (P[2]!, TEF[2]!). — Prov. Antsiranana: Rakotomalaza et al. 853, Marojejy Réserve Naturelle Intégrale, 10.5 km NW of Manantenina, along tributary at head of Andranomifototra River , Camp 4, 1625 m, 14°26’24”S, 49°44’30”E, 9 Nov. 1996, fr. (G!, MO!, P!, TAN!); Rakotonasolo & Ravelonarivo 600, same locality, 1580-1650 m, 25 Feb. 2003, ³ y.fl. (MO!); Rakotonasolo & Ravelonarivo 601, same locality, ³ y.fl. (MO!). Prov. Fianarantsoa: Ravololonanahary et al. 7, Ranomafana National Park , piste touristique de Vohiparara, à l’Est du village de Vohiparara, 1020-1170 m, 21°14’S, 47°23’E, 8 Oct. 1996, fr. (MO!, P!, TAN!); Rogers et al. 63, Ranomafana National Park (Parcel 1), along piste A, 1140 m, 21°14’12”S, 47°23’47”E, 17 Jan. 2003, fr. (MO!, P!, TAN!); Rogers et al. 64, same locality, fr. (MO!, P!, TAN!); Rogers et al. 65, same locality, fr. (MO!, P!, TAN!); Rogers et al. 66, same locality, st. (MO!). — Prov. Toamasina: Andrianjafy et al. 144, Parc National de Zahamena , près compound d’Andalentitra, 1240-1400 m, 17°52’47”S, 48°44’21”E, 28 Sept. 2001, fr. (MO!); Dorr & Barnett 3190, Analamazoatra Réserve Spéciale, [18°56’S, 48°25’E], 2-5 Nov. 1984, fr. (MO!, TAN!); Perrier de la Bâthie 4675, Forêt d’Analamazoatra, [18°56’S, 48°26’E], fr. (P[2]!); Razafitsalama et al. 491, Parc National Mantadia, [18°50’S, 48°28’E], 27 Oct. 2003, fr. (TAN!); Razakamalala 748, Analamazoatra Réserve Spéciale, 1000 m, 18°56’12”S, 48°25’10”E, Sept. 2003, fl. (MO!, P!, TAN!); Rogers et al. 46, same locality, 1000 m, 18°56’12”S, 48°25’10”E, 10 Jan. 2003, fr. (MO!, P!, TAN!); Rogers et al. 169, same locality, 26 Feb. 2003, st. (MO!); Rogers et al. 170, same locality, 26 Feb. 2003, st. (MO!); Rogers et al. 171, same locality, 26 Feb. 2003, st. (MO!); Service Forestier s.n., Analamazoatra-Perinet, S.P. 36, 20 Dec. 1951, st. (TEF!); Service Forestier (Raderasolo) 4411, same locality, 15 Oct. 1951, fl. (TEF!); Service Forestier (Gachet) 17898, same locality, 20 Feb. 1958, fr. (P!, TEF!); Service Forestier (Capuron) 18052, same locality, 29- 30 July 1957, y.fl. (P!, TEF!); Service Forestier (Capuron) 24346, same locality, 21 Dec. 1965, fr. (K!, MO!, P!, TEF!); Service Forestier 34058, Firaisana Andasibe, Fivondronona Moramanga, Ampangalatsary, crête Nord, [1000 m], [18°56’S, 48°26’E], 6 Sept. 1990, fl., fr. (MO!, TEF!); Service Forestier (Comtet) 34480, Fokontany Faliarana, Firaisana Andasibe, Fivondronona Moramanga, village le plus proche Faliarana, au bord de la rivière de Iofa, [18°47’S, 48°33’E], 15 Oct. 1993, fr. (TEF[2]!). — Prov. Toliara: Messmer et al. 114, Andohahela National Park, parcelle 1, 15 km NW of Eminiminy, 1500 m, 24°34’10”S, 46°43’55”E, 24 Nov. 1995, fr. (G!, MO!) .