Rinorea callmanderi Wahlert, 2016

Wahlert, Gregory A., 2016, Novelties from the Northern Mountains Complex of Madagascar IV: A new Rinorea Aubl. (Violaceae) of restricted range from the Galoko and Kalabinono massifs, Candollea 71 (2), pp. 205-210 : 206-209

Rinorea callmanderi Wahlert , spec. nova ( Fig. 1 ).

Typus: MADAGASCAR. Prov. Antsiranana: Ambilobe, Beramanja, Anketrabe, forêt de Kalabenono, 13°38’50”S 48°40’34”E, 778 m, 23.XI.2006, fl., Callmander et al. 582 (holo-: G [ G00341675 ]!; iso-: K!, MO!, P [ P00853251 ]!, TAN) .

Rinorea callmanderi Wahlert is similar to R. mutica (Tul.) Baill. by its opposite-leaved phyllotaxy and contracted, subsessile, few-flowered cymose inflorescence, but differs by its oblanceolate leaves to 13 cm long (vs. broadly oval-elliptic leaves to 9 cm long in R. mutica ), the inner surface of the petals sparsely pubescent near the middle (vs. the inner surface with a tuft of hairs near the apex), the presence of a linear, ventral scale on the anther connective (vs. ventral scale absent), and the presence of an ovate dorsal scale on the anther connective (vs. dorsal scale absent).

Shrub to 3 m tall; young branches flattened in cross section, glabrous to puberulent; stipules not seen. Leaves opposite, equal to anisophyllous; petiole 1.5-5 mm long, glabrous; blade 4-13 × 1.2-5 cm, oblanceolate, glabrous on both surfaces; base attenuate-cuneate, symmetrical, aequilateral to suboblique; secondary vein pairs 6-9, divergent to ascending, tertiary veins reticulate; margin serrulate, often revolute; apex acuminate;

D 1 cm A 2 cm

3 mm C

1 mm

B 1 cm

]

domatia absent. Inflorescence a terminal few-flowered cyme to 2 cm long; peduncle 4-5 mm long, glabrous; pedicels 0.9-1.6 mm long, glabrous; pedicel bractlets persistent, triangular to subulate, 0.7-1 × 0.5-0.8 mm, glabrous, keeled, margin ciliate, apex acute, mucronate. Flowers 3.5-3.9 mm long. Sepals unequal, ovate-deltoid, 0.9-1.8 × 1-1.2 mm, keeled, glabrous, margin ciliate, apex acute to rounded, usually mucronate. Petals subequal, lanceolate, 3-3.3 × 1.1-1.3 mm, outer surface glabrous, inner surface sparsely pubescent near the middle, margin entire to ciliolate, apex subacute to acute, erect. Stamens 2.7-2.8 mm long; staminal tube 0.4-0.5 mm tall, outer and inner surfaces glabrous; anthers subsessile, filaments c. 0.1 mm long, anthers c. 0.7 × 0.5 mm; anther ventral connective scales linear, 0.4-0.5 × 0.1-0.15 mm, apex bifid; anther dorsal connective scales 1.4-1.5 × c. 1.0 mm, apical, ovate, scarious, drying white, surface glabrous, margin entire, apex acute. Pistil 2.7-2.8 mm long; ovary ovoid, 0.5-1 × c. 0.5 mm, glabrous; style 2-2.2 mm long, erect, fluted in crosssection, straight, glabrous. Fruit not seen.

Etymology. – The new species is named in honor of Martin W. Callmander, who collected the type material while he was coordinating the “Northern Highlands project” in Madagascar (see Callmander et al., 2009). Martin has collected extensively throughout Madagascar, among other areas, and his excellent field collections have helped to advance the knowledge of the Malagasy flora, as well as the taxonomy and diversity of other taxa, especially the Pandanaceae .

Distribution and ecology. – The species is known only from the Galoko and Kalabinono massifs in Antsiranana Province in Madagascar ( Fig. 2 ), in lowland evergreen tropical forests at an altitude of 200-800 m in the Sambirano Domain (sensu Humbert, 1955).

Phenology. – Based on herbarium specimen label data, the species flowers in November; fruiting specimens have not been collected.

Conservation status. – Rinorea callmanderi is known from only two localities sensu IUCN (2012), which are 7.5 km apart. The lowland tropical evergreen forests of the Galoko and Kalabinono massifs are now protected but are still threatened by human activities; particularly slash and burn agricultural practices. With only two threatened locations and a restricted range distribution, R. callmanderi is assigned a preliminary conservation status of “Endangered” [EN B1ab(iii)+ B2ab(iii)].

Notes. – Rinorea callmanderi is morphologically most similar to R. mutica , but is easily differentiated by its longer, lanceolate leaves to 13 cm long (compared to broadly ovalelliptic leaves to 9 cm in R. mutica ), the sparse pubescence near the middle of the inner surface of the petal (vs. a tuft of hairs at the base of the inner surface of the petal), and by the anthers which bear ventral and dorsal connective scales, both of which are absent in R. mutica —a unique character state for the subsection. Based on herbarium specimen label data, the distributions of R. callmanderi and R. mutica appear to be non-overlapping. Rinorea callmanderi is known only from the Galoko and Kalabinono massifs at elevations of 200-800 m, whereas R. mutica is almost entirely confined to Nosy Be island at elevations of 20- 300 m. A single collection of R. mutica is recorded from the “montagnes de Sambirano” (Perrier de la Bâthie 5045), at an elevation of 600 m, but the species has not been collected from the Galoko or Kalabinono massifs (Wahlert, 2010). Both R. callmanderi (as “ Rinorea sp. nov. 1”) and R. mutica were sampled in the phylogenies of Wahlert & Ballard (2012) and van Velzen et al. (2015). The results from both studies recovered the two species in a highly supported Verticillatae clade, but no relationships among species were resolved within the clade. Based on the opposite-leaved phyllotaxy and similar floral structure shared by other species in the subsection, as well as the results from molecular phylogenies, R. callmanderi is placed in R. subsect. Verticillatae. The description of R. callmanderi now brings to 19 the number of species belonging to the subsection, however, further study is needed for a comprehensive understanding of the species diversity within the group.

Paratypus. – MADAGASCAR. Prov. Antsiranana: Ambilobe, Beramanja, Anketrabe, Belinta, forêt de Galoka, 13°35’23”S 48°42’43”E, 210 m, 6.X.2013, fl. bud, Razakamalala et al. 7669 ( G, MO, P, TAN) .

Figures

Fig. 1. – Rinorea callmanderi Wahlert. A. Inflorescence; B. Flowering branch; C. Flower; D. Leaf, abaxial surface. [Callmander 582,G] [Drawing: R. L. Andriamiarisoa

Fig. 2. – Distribution map of Rinorea callmanderi Wahlert (stars) in Madagascar plotted on a map of forest cover in 2000 (grey) following HARPER et al. (2007). Areas outlined in black are protected areas.