Cyphostemma darainense Wahlert & Phillipson

Wahlert, Gregory A., Phillipson, Peter B., Nusbaumer, Louis & Gautier, Laurent, 2012, Cyphostemma darainense Wahlert & Phillipson (Vitaceae), a new species from northeastern Madagascar, Candollea 67 (2), pp. 277-283 : 278-283

Cyphostemma darainense Wahlert & Phillipson , spec. nova

( Fig. 1 - 4 ).

Typus: MADAGASCAR. Prov. Antsiranana: Vohemar, Daraina, forêt d’Andranotsimaty , à 10 km au Nord-est de Daraina, 13°11’04”S 049°42’24”E, 182 m, 14.XI.2005, fr., Randrianaivo & al.1308 (holo-: P; iso-: CNARP, MO [ 6028348 ], TAN) .

Cyphostemma darainense Wahlert & Phillipson issimilar to C. echinocarpa Desc. , but differs by the acuteapex of the stipule, the obovateleafletswithrounded or mucronate apices, and the shorter peduncle.

Plant a pachycaul, with a swollen, semi-succulent, bottleshaped trunk up to 2 m tall, with 1-few lianescent stems growing from the apex of the trunk. Stems up to 6 m long, subwoody, young stems sparsely pubescent; nodes slightly swollen, pubescent; stipules caducous, narrowly triangular, 3.5-5 0.7-1.1 mm, pubescent, margin ciliate, apex acute; young tendrils sparsely pubescent, apex bifid, subpersistent; mature tendrils becoming glabrous. Leaf compound, imparipinnate with (2-)3 pairs of lateral leaflets, 13-25 cm long (including petiole), 7-11 cm wide; rachis pubescent when young, becoming sparsely pubescent, extending 2-3 cm beyond the upper pair of lateral leaflets; petiole 4.5-8 cm long; lateral and terminal leaflets similar, obovate or rarely ovate or suborbicular, 3-5.8 cm long, 2.2-4.2 cm wide, base cuneate, rounded, or truncate, apex rounded or obtuse, mucronate, mucro 1-3 mm long, margin finely denticulate, ciliate, young leaves densely pubescent, becoming sparsely pubescent or glabrous; petiolules 1-4 mm long, pubescent; primary vein visible on both surfaces, sparsely pubescent on lower surface, minutely pubescent on upper surface towards the base; secondary veins visible on lower surface, not clearly visible on upper surface, sparsely pubescent on lower surface, tertiary venation reticulate. Inflorescence a leaf-opposed, compound dichasial cyme, open, flat-topped, c. 7-10 cm wide, rachis sparsely pubescent, peduncle 3.5-7.5 cm long, bracteoles ovate to broadly triangular, c. 0.3 0.3 mm, margin ciliate. Flower bud cylindrical and slightly constricted near the middle, 1.8-2.5 mm long, 1.4-2 mm wide at the base, glabrous; pedicel 4-12 mm long, thickened near the calyx, sparsely pubescent to glabrous. Calyx a fused membranous flange, 0.4-0.6 mm tall, ciliate at the summit. Corolla pale yellow, petals four, linguiform, glabrous, 3-3.5 mm long, 1-1.5 mm wide at the base, 0.8-1, apex rounded, ± hooded, margin entire, with 6-10 parallel veins. Stamens four, oppositipetalous, 1.8-3.8 mm long, filament 1.7-2.1 mm long, anther dorsifixed, oblate, 0.5-0.7 0.5-0.7 mm; nectary glands four, alternipetalous, square to rectangular, 0.6-0.8 0.7-1.1 mm, fused to the base of the ovary. Ovary ovoid, 0.8-0.9 0.7- 0.8 mm, glabrous, style cylindrical, glabrous, c. 0.6 mm long. Fruit a berry, subspheroid, green, c. 2 1.5 cm, glabrous. Seed reniform-obovoid, beaked, with a raphe, c. 13 7 mm.

Etymology. – The specific epithet refers to the locality of Daraina in the central part of the Loky-Manambato region which is the only known region of occurrence for the new species.

Distribution. – The species is only known from the forests of Loky-Manambato. Fifty-eight individuals were observed among more than 54,000 plant occurrences identified during a vegetation study of the region. It is frequent in several forests subareas of this region, including: Ampondrabe, Bekaraoka, and Solianampilana, and less frequently in Ankaramy, Bobankora, and Antsahabe.

Habitat and ecology. – Cyphostemma darainense grows primarily in dry forests or in ripicolous vegetation within dry forests, and uncommonly to rarely in mesophyllous, arbustive saxicolous, or sclerophyllous forest types. It occurs on thin substrates, generally among stones or on rocky outcrops. The species was observed at low elevations, between 100 and 550 m, on level ground or slopes, but never on ridge crests. The species does not grow in sites that do not provide stability for the swollen, semi-succulent trunk. The absence of the species from crests and steep slopes may indicate that it is susceptible to windthrow. Cyphostemma darainense grows in forests with canopies reaching 8 to 10 m, with emergent trees reaching 10 to 14(- 18) m, with a sparse arbustive strata 2 to 4.5 m high, and a sparse suffrutescent strata less than 1 m high.

The most frequent species recorded together with C. darainense in vegetation surveys are, in decreasing abundance: Drypetes perrieri Leandri , Cynometra commersoniana Baill. , Dialium occidentale subsp. septentrionale Du Puy & R. Rabev. , Grevea madagascariensis Baill. , Dracaena reflexa Lam. , Strychnos decussata (Pappe) Gilg, Ehretiacymosa Thonn., Baudouiniasollyaeformis Baill. , Dracaena xiphophylla Baker, Drocelonciarigidifolia (Baill.) J. Léonard , Mallotus oppositifolius (Geiseler) Müll. Arg. , and Gyrocarpus americanus subsp. tomentosus Kubitzki.

Potential distribution. – Results from modeling the potential distribution of Cyphostemma darainense show the species to have an affinity with the environmental conditions present in the eastern forests of Loky - Manambato ( Fig. 5 ). The three most important environmental variables that appear to delimit its distribution are: a) annual mean temperature less than 19°C, b) slopes greater than 28° (at higher temperatures), and c) cloud cover less than 20% during the dry season.

Conservation status. – With an “Extent Of Occurrence” (EOO) of 551 km 2, an “Area Of Occupancy” (AOO) of 76 km 2, and 8 subpopulations, 5 of which are in the Loky-Manambato protected area, C. darainense is assigned a preliminary status of “Endangered” (EN) following IUCN (2001) (calculation following MOAT, 2007, and CALLMANDER & al., 2007).

Paratypi. – Madagascar: Antsiranana Province, Vohemar District, Daraina, Mahatsara , Ambilondambo (Ambilondamba) à 8 km au Nord de Daraina, 13°09’45”S 049°38’49”E, 326 m, 17.XI.2005, fr., Be &al. 292 ( CNARP, G, MO, P [2 sheets], TAN); Ampisikina, Tsaratanana, forêt d’Ampondrabe , à 1 km au Nord ouest du village d’Ambaribe, 12°58’18”S 049°41’57”E, 200 m, 4.XI.2005, fr., Rakotonandrasana & al. 968 ( CNARP, MO, P, TAN); Daraina, Befarafara, forêt de Solanampilana , Ankoakala, à 2 km au Sud de Befarafara, 13°05’26”S 049°34’ 32”E, 100 m, 15.XI.2005, fr., Rakotonandrasana & al.987 ( CNARP, G, MO, P, TAN); Ampisikina (Ampisikinana) Soatanana, Ambarilao, forêt d’Ampondrabe , 12°57’39”S 049°42’ 31”E, 175 m, 5.XI.2005, fl., Ratovoson & al.1060 ( MO, P, TAN); Daraina, forêt d’Ankaramy , à 1330 m du point côté 215, au 123°, 13°17’30”S 49°40’47”E, 330 m, 21.XII.2005, fr., Ranirison & Nusbaumer 1037 ( G, K, MO, P, TEF) .

Figures

Fig. 1. – Cyphostemma darainense Wahlert & Phillipson. A. Inflorescence; B. Flower showing corolla and fused, flange-like calyx; C. Stamen and nectary glands; D. Fruit; E. Ovary; F. Petal; G. Immature leaflet; H. Node and stipules. [Ratovoson & al. 1060, MO] [Drawn by R. L. Andriamiarisoa]

Fig. 2. – Cyphostemma darainense Wahlert & Phillipson. A. Dried fruit; B. Leaflet; C. Infructescence. [Be & al. 292, CNARP] [Drawn by R. L. Andriamiarisoa]

Fig. 3. – Field photograph showing fresh leaves and mature fruits ofCyphostemma darainense Wahlert & Phillipson.

Fig. 4. – Field photograph showing pachycaulous habit of the trunk of Cyphostemma darainense Wahlert & Phillipson. [Ranirison & Nusbaumer 1037, G] [Photo: L. Nussbaumer]

Fig. 5. – Map of Loky-Manambato area showing actual distribution of Cyphostemma darainense Wahlert & Phillipson (red dots), potential distribution (black shading), and area not predicted for its distribution (white). [Forest acronyms: Abd: Ambilondamba, Ank: Ankaramy, Apb: Ampondrabe, Atb: Antsahabe, Atd: Ambohitsitondroina, Atg: Antsaharaingy, Bek: Bekaraoka, Bin: Binara, Sol: Solaniampilana].