Lemurodendron Villiers & P. Guinet, Bull. Mus. Natl. Hist. Nat., B, Adansonia 11(1): 3. 1989.

Figs 144, 145, 146, 147

Type.

Lemurodendron capuronii Villiers & P. Guinet

Description.

Unarmed trees to 30 m and 1 m stem diameter (Fig. 144B, C); brachyblasts absent. Stipules caducous. Leaves bipinnate, petiole with discoid glands between pinnae; pinnae 1-2 pairs; leaflets 2-4 pairs per pinna, obovate, slightly asymmetrical, the apex rounded and notched to subtruncate, mucronate, glabrous, midvein more or less central, with 3-5 pairs of lateral veins, the basal pair very long. Inflorescences loose-flowered, short spikes (Fig. 145A), combined into a terminal panicle. Flowers with the sepals valvate in bud, petals valvate, basal flowers often sterile, apical flowers hermaphrodite; calyx, scarcely lobed, porcelain white, petals connate to near tips, obovate, the free tips subacute, pure white; basal flowers with staminodes 10 or fewer, filiform, or long (ca. 7 mm) and flattened within the same flower, gynoecium reduced; apical flowers hermaphrodite with 10 free stamens, anthers ovoid with a caducous apical gland, ovary subsessile, narrow ellipsoid, ca. 2 mm long, style slender, 3-4 mm long, stigma tubular and flared; pollen in acalymmate tetrahedral tetrads. Fruits narrowly linear-oblong, strap-like, straight (Fig. 146A), held erect above shoots, (8) 15-35 × 2-2.5 cm, ca. 10-seeded, the base cuneate, the apex obtuse to acute, valves glabrous, the blackish exocarp breaking away, dehiscent along both sutures. Seeds broadly winged, oblong, 30-50 × 16-24 mm including the 5-10 mm broad wing, testa lacking a pleurogram.

Chromosome number.

Unknown, but many gene duplications suggestive of a polyploid (Ringelberg et al. unpubl. data).

Included species and geographic distribution.

Monospecific ( L. capuronii), a very narrowly restricted endemic in north-eastern Madagascar, known from just a handful of collections from the 1950s and 1960s, but recollected in 2014 from south of Vohemar, Antsiranana (Fig. 147).

Ecology.

Mixed lowland evergreen and deciduous forest on igneous rock (gabbro), to 200 m elevation. Seeds likely wind-dispersed.

Etymology.

From Greek, lemur and - dendron (= tree), in reference to the endemic distribution of the genus in Madagascar where extant lemurs are also endemic.

Human uses.

The wood is locally harvested for making charcoal, potentially threatening the survival of this globally very rare genus (Erik Koenen, field observation).

Notes.

Lemurodendron is sister to Neptunia in recent phylogenomic analyses (Koenen et al. 2020a), a perhaps surprising result given the disparate morphologies of these two genera, but support for this relationship is robust (Fig. 143; Ringelberg et al. 2022). The glossy pure white sepals and petals of Lemurodendron flowers are unique within Caesalpinioideae and the erect disposition of the long strap-like pods is unusual. Winged seeds are rare within the Dichrostachys clade, found only in Lemurodendron (broadly-winged seeds) and Mimozyganthus (very narrowly-winged seeds).

Taxonomic references.

Villiers (2002); Villiers and Guinet (1989), including illustration.