Eremolaena, Baill.

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 : 14

EREMOLAENA Baill.

Bull. Mens. Soc. Linn. Paris 1: 413 (1884).

TYPE. — Eremolaena humblotiana Baill.

The genus Eremolaena comprises two species, both of which have been recognized for many decades. Vegetatively they closely resemble several species in the two putatively related genera, including Pentachlaena orientalis , Perrierodendron capuronii , and P. occidentalis , and can sometimes be difficult to recognize without flowers and/or fruits. Distinctive features of the genus include strongly unequal sepals (the outer two being much smaller), an ovary with 3 carpels (vs. 2 in Perrierodendron and 5 in Pentachlaena ), and a dehiscent fruit (also present in Pentachlaena ) containing only 2 seeds in each locule.

Key to the species of Eremolaena

1. Leaves subcoriaceous, largest blades at least 9 cm long, secondary and tertiary venation distinctly raised on abaxial surface; sepals 15-19 mm long at anthesis; flowers borne in pairs, subtended by 5 small, scale-like involucral lobes; humid and subhumid forest on laterite, Betampona RNI, Lac Alaotra region, and Brickaville to Vatomandry ................................................................................................................ 1. E. humblotiana

1’. Leaves chartaceous, largest blade not exceeding 5(-6) cm long, secondary and tertiary venation weakly raised on abaxial surface; sepals 9-12 mm long at anthesis; flowers borne singly, subtended by a very small, 3-lobed collar; littoral forest on sand, Masoala PN to Ft. Dauphin area ........................................ 2. E. rotundifolia

Clé des espèces d ’ Eremolaena

1. Feuilles subcoriaces, limbes les plus grands mesurant au moins 9 cm de long, nervation secondaire et tertiaire distinctement proéminente sur la face abaxiale; fleurs géminées, portées par un involucre de 5 petits lobes en forme d’écailles; sépales de 15-19 mm de longueur à l’anthèse; forêt humide et subhumide sur latérite, RNI de Betampona, région du Lac Alaotra, et de Brickaville à Vatomandry ............................ 1. E. humblotiana

1’. Feuilles chartacées, limbes les plus grands ne dépassant pas 5(-6) cm de long, nervation secondaire et tertiaire faiblement proéminente sur la face abaxiale; sépales de 9-12 mm de long à l’anthèse; fleurs solitaires, portées par une très petite collerette 3-lobée; forêt littorale sur sable, du PN de Masoala à la région de Ft. Dauphin .......................................................................................................................................... 2. E. rotundifolia