Pentachlaena

Lowry Ii, Porter P., Haevermans, Thomas, Labat, Jean-Noël, Schatz, George E., Leroy, Jean-François & Wolf, Anne-Elizabeth, 2000, Endemic families of Madagascar. V. A synoptic revision of Eremolaena, Pentachlaena and Perrierodendron (Sarcolaenaceae), Adansonia (3) 22 (1), pp. 11-31 : 16

Key to the species of Pentachlaena

1. Inflorescences terminal, branched, with ca. 10 flowers; leaves obovate, with 5-6 pairs of secondary veins, apex distinctly emarginate; Betampona RNI .............................................................. 1. P. betamponensis

1’. Inflorescences axillary and occasionally terminal, with 2 flowers; leaves elliptic to orbicular, with (7-)8-12 pairs of secondary veins, apex rounded to truncate, rarely somewhat emarginate ...................................... 2

2. Leaves elliptic, strongly discolorous, largest blade 9.5-18 × 7-12 cm; peduncles at least 15 mm long; bracts subtending flowers 10-15 mm long, deeply laciniate; seeds pubescent; sublittoral forest on sand overlaying laterite, Tampolo STF, Analalava, Betampona RNI ............................................................ 2. P. orientalis

2’. Leaves broadly elliptic to orbicular, weakly discolorous, largest blade 5-9 × (3.5-) 4-7 cm; peduncles less than 8 mm long or flowers subsessile; bracts subtending flowers to 5-7 mm long, entire or slightly dentate; seeds glabrous; Tapia woodland on outcrops of quartzite and perhaps other substrates, Col des Tapias, Ibity and area immediately S .......................................................................................................... 3. P. latifolia