Memecylon perditum R.D.Stone, 2006

Stone, Robert Douglas, 2006, New species of Memecylon L. and Warneckea Gilg (Melastomataceae) from Madagascar and Mayotte, Adansonia (3) 28 (2), pp. 337-358 : 346

Memecylon perditum R.D.Stone , sp. nov.

( Fig. 5 )

A speciebus ceteris Memecyli madagascariensis combinatione foliorum obovatorum, cymularum breviter pedunculatarum ad axillas foliorum vel nodos aphyllos defoliatosve, florum usque 3 subsessiliumque ad par bractearum cucullatarum subtentorum cum floribus centralibus itidem bibracteolatis, connectivo antherarum dorsaliter glanduloso, fructuum globosorum 6 mm diametro distinguenda.

TYPUS. — Madagascar. Antsiranana province, Masoala peninsula, valley of Iketra river, affluent to the Anaovandrano , along foot path between Iketra and Antanambao Rantavato (valley of Ampanavoana river ), 15°43’05”S, 50°13’05”E, alt. c. 50 m, understory of evergreen rain forest, 6.XII.2001, Stone et al. 2402 (holo-, CAS; iso-, CAS, K, MO, P, TAN) .

PARATYPES. — Madagascar. Antsiranana province, Besamatrakely forest, Ambanja , XII.1963, Rakotozafy 341 ( P) . — Antsiranana province, Réserve naturelle intégrale de Marojejy, near summit of Ambatosoratra, 14°32’S, 49°42’E, alt. 1583 m, VI .1994, Ravelonarivo et al. 229 (CAS, P).

DESCRIPTION

Evergreen shrub or tree 5-30m high; branchlets terete and becoming ± thickened at the nodes; successive nodes alternately bearing normal leaves and floral bud scales (modified leaves); internodes 1-2.5 cm long.Leaves with petioles 3-7 mm long; blades thinly coriaceous, granular-rugose on both surfaces (when dry), obovate, 3.5-6 cm long, 1.7-3.3 cm wide, attenuate at base then decurrent with the petiole, rounded and obtuse or even slightly retuse at apex; only the mid-nerve clearly visible, canaliculate on the upper surface, ± prominent on the lower toward the base; transverse veins obscure or faintly visible on the lower surface, oblique relative to the mid-nerve. Cymes contracted, less than 1 cm long, 1-3-flowered, borne either in the leaf axils, at the intervening (scale-bearing) nodes, or at the defoliated nodes of older branchlets; peduncles 1-2.5 mm long, axes absent or very short; bracts persistent, lanceolate, c. 1 mm long, acute to apiculate at apex, cucullate, connate at base; bracteoles subtending only the central flower, approximately the same length and shape as the bracts. Flowers subsessile (pedicels up to 0.5 mm long); hypantho-calyx white, cupuliform to slightly urceolate or obconic, c. 3 mm long and 2-3 mm wide; calyx 4-lobed in bud, the margin becoming broadly sinuate and 4-microdentate at anthesis. Corolla acute to shortly acuminate in bud; petals violet, lanceolate-acuminate, 3.5 mm long, c. 1 mm wide, the base distinctly auriculate then short-unguiculate (claw to 0.5 mm long). Anthers c. 2 mm long, the connective narrowly conic-acute, the pollen sacs frontal and extending for about half the length of the connective on the ventral side, the dorsal gland elliptic and medially positioned; filaments not seen. Style 6-7 mm long; ovules 16. Fruits slightly oblong when immature but becoming globose, 6 mm in diameter, with persistent calycinal crown; epigynous chamber lacking radial partitions.

REMARKS

In Jacques-Félix (1985a), M. perditum would key to the group of species that includes M. bernieri Cogn. , M. peracuminatum H.Perrier , and M. bracteatum Jacq. -Fél., on account of the anther connectives bearing a dorsal gland and the subsessile flowers each immediately subtended by a pair of bracts or bracteoles. The inflorescences of M. perditum appear most similar to those of M. bracteatum , except that in M. bracteatum the bracteoles subtending the central flower are larger (2.5 × 2 mm) and ovate to suborbicular (not lanceolate). The leaves of M. bracteatum are also very different in being lanceolate-acuminate (as are those of M. peracuminatum ). Memecylon bernieri is like M. perditum in having leaves that are rounded at the apex, but its blades are narrowly oblanceolate (not obovate). The small, squamiform bracts and bracteoles of M. bernieri also differ from those of M. perditum .

Figures

FIG. 5. — Memecylon perditum R.D.Stone: A, habit; B, inflorescence with flower buds; C, open flower with stamens and two petals removed; D, anther and part of filament. Stone et al. 2402. Scale bars: A, 5 cm; B, C, 2 mm; D, 1 mm.