Benthamia exilis Schltr.

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 : 200-201

Benthamia exilis Schltr.

( Fig. 40 )

Repertorium Specierum Novarum Regni Vegetabilis 33: 26 ( Schlechter 1924).

Benthamia exilis var. tenuissima Schltr., Repertorium Specierum Novarum Regni Vegetabilis 33 ( Schlechter 1924: 26). —

Type: Madagascar • Vakinankaratra , Mt. Tsiafajavona; 19°21’25”S, 47°18’28”E; alt. 2400 m; III.1921; H. Perrier 13522; lectotype: P[P00094501]!, designated here; isolectotype: P[P00094502]!, syn. nov .

TYPE MATERIAL. — Madagascar • Haute Matsiatra, massif d’Andringitra ; 22°07’28”S, 46°52’07”E; alt. 2200 m; IV.1921; H. Perrier 13652; lectotype: P [ P00094498 ]!; isolectotype: P [ P00094499 ]!, designated by Hermans et al. (2007: 70) .

ETYMOLOGY. — From the Latin “ exilis ”: slender, meagre, thin.

PHENOLOGY. — January to April.

DISTRIBUTION AND ECOLOGY. — Madagascar. So far only known from Mt. Tsiafajavona in the Vakinankaratra region and the Andringitra massif in Haute Matsiatra region, in montane grasslands, at elevations ranging from 1700 to 2400 m ( Fig. 41 ).

CONSERVATION. —Known only from two localities, Mt.Tsiafajavona and the Andringitra massif, this species has been seldom collected and is considered Endangered (EN), according to criterion B2, with fewer than five known localities and threatened habitat.

ADDITIONAL SPECIMENS EXAMINED. — Madagascar • Haute Matsiatra, massif d’Andringitra; alt. 2200 m; II.1922; H. Perrier 14390; P [ P00094500 ] ! • Haute Matsiatra, massif d’Andringitra; alt. 2200 m; II.1922; H. Perrier 14579; P [ P00094503 ]! for Benthamia exilis var. tenuissima • Haute Matsiatra, Andringitra ; 2001; J. Hermans 2063; K!.

NOTES

The specimens available show a variation of habit from 12 cm to about 50 cm high and a great variation of rachis length. Considering this variability we include Benthamia exilis var. tenuissima Schltr. in the synonymy of B. exilis . For this variety Schlechter cited Perrier 13522 for the type, but there are in P two specimens with this collection number. We have chosen P00094501 as lectotype because Perrier indicated on it that it was sent to Schlechter in April 1921.

Plants referred to var. tenuissima in Hervouet (2018: 162) are Cynorkis micrantha (Frapp.ex Cordem.) Schltr. In the same page 162 the specimen cited Perrier 74579 should read Perrier 14579.

An undescribed species close to B. exilis has been observed on the summit of Ambondrombe, but with a much longer midlobe of the lip. No herbarium specimen has been located. See also the notes under Benthamia micrantha in excluded species.

See also: Schlechter (1930: t.10 n°38), Perrier (1939: 20); Cribb & Hermans (2009: 43), Hervouet (2018: 162, the bottom photograph is Cynorkis micrantha ).

DESCRIPTION

Very slender terrestrial herb, 13-50 cm tall. Tubers oblong and smooth. Stem filiform, 0.8-1.5 mm in diameter, covered by 4-7 distant sheaths with blade acute. Leaves absent. Rachis 8 × 1-1.2 cm, rather dense, many-flowered. Floral bracts lanceolate, almost as long as the flowers, 2.8-5 × 1-1.2 mm. Ovary fusiform-cylindrical,smooth, 4-5 × 0.8 mm. Flowers yellowish or greenish,sometimes with brown sepals;sepals oblong, somewhat obtuse, 2-3.5 × 0.8-1.5 mm, 3-veined, the dorsal sepal concave, the laterals oblique; petals oblong, obtuse, 1.9-3.1 × 0.9-2 mm, 3-veined and slightly expanded at the anterior edge in the lower half; lip narrowly oval in outline, 3-4.1 × 1.6-2.5 mm, almost orbicular and concave in its basal half, narrowly lanceolate and obscurely trilobed in the apical half, midlobe about 1.8 mm; spur with a wide base, narrowly cylindrical towards the apex, 1.8-3 × 0.3-0.4 mm long and bifid at the tip. Anther obtuse and short, 0.6-1.2 × 0.5-0.8 mm; auricles erect, linear, curved in a scythe shape and taller than the anther.

Figures

FIG. 40. — Benthamia exilis Schltr., Andringitra Massif, Madagascar,12 March 2009. Photograph by Jean-Michel Hervouet.

FIG. 41. — Distribution map of Benthamia exilis Schltr.