Benthamia A.Rich.

Hervouet, Jean-Michel, Descourvières, Pascal, Hermans, Johan & Longou, Ludivine, 2025, Revision of the genus Benthamia A. Rich. (Orchidaceae, Orchidioideae, Habenariinae), Adansonia (3) 47 (11), pp. 171-249 : 176

Genus Benthamia A.Rich.

( Figs 1 ; 2 )

Monographie des Orchidées des Îles de France et Bourbon ( Richard 1828: 37), non Lindl. (w).

Rolfeella Schltr., Repertorium Specierum Novarum Regni Vegetabilis 33: 18 ( Schlechter 1924). — Type species: Benthamia glaberrima (Ridl.) Schltr.

TYPE SPECIES. — Benthamia latisatis (Thouars) Bytebier (as Benthamia latifolia A.Rich. ).

DISTRIBUTION AND ECOLOGY. — The genus Benthamia is widespread in Madagascar, La Réunion and Mauritius, with possibly one species (probably B. africana (Lindl.) Hermans ) on the Comoros ( Fig. 3 ). It ranges from sea level to high altitudes (2600 m). It is generally found in open places, both dry and marshy.

ETYMOLOGY. — Named for the English botanist George Bentham (1800-1884), who together with Sir Joseph Hooker produced Genera Plantarum (1865-1883).

DESCRIPTION

Terrestrial or less commonly epiphytic (5 species) sympodial glabrous herbs with 2-7 swollen generally glabrous tubers, which are in fact tuberous roots. Stem erect or arcuate, sometimes with sheaths only (one species), or with 1-2 radical sheathing leaves, or with 2-10 cauline leaves. Leaves lanceolate, ovate or elliptic, sometimes not developed at anthesis (3 species). Rachis terminal, erect or rarely curved, few- to densely many-flowered. Floral bracts small, usually as long or longer than the ovary. Ovary pedicellate, fusiform or oblong, generally twisted (except Benthamia bosseri ). Flowers small, resupinate (except one species with non-resupinate and pendent flowers), arranged in a narrow rachis, white, green or yellow; sepals and petals free or almost free, entire; labellum entire or trilobed; spur cylindrical (nine species) or short and scrotiform, entire or bilobed at apex, or a small hollow only in one species ( B. boiteaui ). Column short and massive, subterete, erect; anther erect to slightly deflexed, placed above the rostellum, apiculate or not, bilocular, locules parallel, without anther canals; pollinia two, ellipsoid, granular, 2 caudiculae rudimentary, with two viscidia, detachable, flat, ovate or subelliptic; rostellum small, tridentate or trilobed at the anterior edge; stigma always very short, cushion-shaped, with short convex lobes; auricles two, generally conspicuous, subspathulate or falciform, sometimes lacerated, on lateral sides of column. Fruit a dehiscent capsule, with floral parts persistent on the fruit.

Figures

FIG. 1. — Benthamia latisatis (Thouars) Bytebier, specimen P00334779, showing the different parts of the plant: A, rachis; B, sterile bract; C, stem (including the peduncle); D, leaf; E, sheath. Photograph by Jean-Michel Hervouet.

FIG. 2. — Sketch by Pascal Descourvières showing the different parts of a Benthamia A.Rich.flower:A, floral bract;B, profile of flower with spur;C, ovary;D, dorsal sepal; E, petal; F, lateral sepal; G, front view of spur; H, profile of column; I, rostellum; J, auricle; K, lip; L, front view of flower; M, stigmatic cavity; N, rostellum. Scale bars: A-F, H-L, 2 mm; G, 1 mm.

FIG. 3. — Distribution maps of the genus Benthamia A.Rich.