Benthamia boiteaui Hervouet

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 : 185-186

Benthamia boiteaui Hervouet

( Figs 14 ; 15 )

Adansonia , sér. 3, 36 (2): 213 ( Hervouet et al. 2014).

TYPE MATERIAL. — Madagascar • Haute Matsiatra, Ambondrombe ; 21°52’47”S, 47°15’33”E; alt. 1900 m; 11.IV.1941; P. Boiteau 4621; holotype: P [ P00692438 ]!.

ETYMOLOGY. — Dedicated to Pierre Boiteau (1911-1980), collector of the type and former director of the Tsimbazaza botanical and zoological garden in Antananarivo.

PHENOLOGY. — March to April.

DISTRIBUTION AND ECOLOGY. — Madagascar. In Haute Matsiatra and Amoron’i Mania regions. Always found in damp places in montane grasslands or marshes, from 1000 to 1900 m. During the present study a specimen has been identified from Antoetra, near Ambositra, it remains however rather rare ( Fig. 16 ).

CONSERVATION. — Now known from three different locations, each in very limited areas giving an AOO of less than 500 km ², in habitats of montane grasslands threatened by bush fires, indicating a conservation status as Endangered (EN) according to criterion B2.

ADDITIONAL SPECIMENS EXAMINED. — Madagascar • Haute Matsiatra, Ambondrombe; 21°52’47”S, 47°15’33”E; alt. 1900 m; 11.IV.1941; P. Boiteau 4621; P [ P00692439 , P00692440 ] ! • Haute Matsiatra, Ambondrombe; alt. 1700 m; 11.IV.1941; P.Boiteau 4637; P [ P00692439 , P00692440 ] ! • Haute Matsiatra, Ambondrombe; alt. 1800 m; 12.IV.1941; P. Boiteau 4687; P [ P00692303 ] ! • Amoron’i Mania, Antoetra, piste du Vohibe, sud d’Ambositra; 20°46’27”S, 47°19’16”E; V.1969; P. Morat 3148; P [ P00692448 , P00692449 ] ! • Haute Matsiatra, parc de Ranomafana; 21°11’S, 47°25’E; alt. 1150 m; 10.III.1995; Turk et al. 722; K!, K [spirit 72273.000], MO!, TAN ! • Haute Matsiatra, Ambondrombe; alt. 1900 m; 1999; J. Hermans 4403 ex Malala orchidées; K !.

NOTES

This species shares some similarities with the genus Tylostigma , e.g. the spur is similar to that of Tylostigma nigrescens Schltr. , but the lip lacks a transverse lamellate callus and is typical for Benthamia .

See also: Hervouet (2018: 158).

DESCRIPTION

Erect terrestrial herb 27-38 cm tall. Tubers and roots not seen. Stem cylindrical, 2 mm in diameter, dull pale green, with one or two sheaths above the ground followed, in the first 2/3 rd, by 2-3 leaves, and then in the upper part 1-2 sterile bracts, linear, acute, 15-30 × 2-3 mm. Leaves amplexicaul, flexible, linear and acute, 50-130 × 5-8 mm. Rachis 5-8 cm long, terminal, erect, with 15-33 flowers. Floral bracts acicular, short and obtuse, 0.1-0.3 × 1 mm, adpressed to the ovary. Column apiculate, 1-1.5 × 1-1.2 mm, lateral auricles large, suborbicular; rostellum trilobed, with midlobe apiculate; masullae very small, less than 0.12 mm in diameter. longer than ovary, 4-11 × 1.5-2 mm. Ovary 4.8-7 mm × 1.9- 3 mm. Flowers 6 mm deep, 4.5 mm high, 5 mm wide, bright white; dorsal sepal elliptic, obtuse with a slightly rounded and concave apex, 3-6 mm × 1.2-3 mm; lateral sepals elliptic, 3.1-5.5 × 1.2-3 mm, with a visible vein, dorsally slightly keeled, ventrally slightly concave, apex rounded, sub-acute, margin smooth; petals partly overlapping and together with the dorsal sepal forming a hood over the column and lip, elliptic, 3-4.1 × 1.8-2 mm, with a visible vein, apex rounded, sub-acute, margin smooth or slightly irregular; lip trilobed, 2.5-5 × 1.6-3 mm, lateral lobes acute, 0.5 mm long, central lobe fleshy, 1.0- 1.3 mm long; spur a shallow hollow only, very

Figures

FIG. 14. — Benthamia boiteaui Hervouet, Mount Ambondrombe, Madagascar, 9 March 2009. Photograph by Jean-Michel Hervouet.

FIG. 15. — Benthamia boiteaui Hervouet, Mount Ambondrombe, Madagascar, 9 March 2009. Photograph by Jean-Michel Hervouet.

FIG. 16. — Distribution map of Benthamia boiteaui Hervouet.