Benthamia rostrata 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 : 232-234

Benthamia rostrata Schltr.

( Fig. 87 )

Repertorium Specierum Novarum Regni Vegetabilis 33: 33 ( Schlechter 1924). — Platanthera madagascariensis sensu Schltr., Beihefte zum Botanischen Centralblatt 33: 299 ( Schlechter 1916), non Kraenzl. ( Kraenzlin 1899: 609).

Benthamia perularioides Schltr., Repertorium Specierum Novarum Regni Vegetabilis 33: 32 ( Schlechter 1924). — Type: Madagascar • Vakinankaratra, mont Tsiafajavona; 19°19’58”S, 47°16’08”E; alt. 2500 m; III.1921; H. Perrier 13523; lectotype: P [ P00094567 ]!, here designated; isolectotype: P [ P00094568 ]!, syn. nov .

TYPE MATERIAL. — Madagascar • Vakinankaratra, mont Ibity au sud d’Antsirabe; alt. 2000 m; II.1914; H. Perrier 8101; holotype: P [ P00094574 ]!; isotype: P [ P00094575 ] !.

ETYMOLOGY. — From the Latin “ rostratus ”, beaked, referring to the midlobe of the lip.

PHENOLOGY. — January to April.

DISTRIBUTION AND ECOLOGY. — Madagascar. Widespread in montane grasslands from 1400 to 2370 m. Can also grow on bare laterite soils ( Fig. 88 ).

CONSERVATION. — The conservation status of this species is of Least Concern (LC). It has the largest number of specimens of the genus in herbaria and is still widespread in Madagascar. It has however been assessed EN by IUCN in 2015 (https://doi.org/10.2305/IUCN. UK.2015-2.RLTS.T70102386A70124752.en).

ADDITIONAL SPECIMENS EXAMINED. — Madagascar • sine loc.; Baron 849; P [ P00094569 , as Rolfeella glaberrima , on the same sheet as Dr. Fox 23 but different]!, K [ K000415545 ] ! • sine loc.; R. Baron 5252; P [ P00094570 ] ! • Ankaratra ; R. Capuron 759; P [ P00692268 ] ! • sine loc.; A. M. Homolle 1112; P [ P00692276 ] ! • Ihorombe, plaine de la Menarahaka, entre Ihosy et Ivohibe ; 22°27’S, 46°15’E; B. Descoings 983; P [ P00692270 ] ! • Ankaratra ; G. F. Scott-Elliot 2096; BM [ BM000034590 ] ! • Ankaratra ; G. F. Scott-Elliot 1982; P [ P00334731 ] ! • Central Madagascar ; R. Baron 2271; K ! • sine loc.; R. Bonet s.n.; P [ P00326135 ] ! • Analamanga, Tampoketsa d’Ankazobe ; E. Ursch 1019; TAN!, P [ P00692272 ] ! • Analamanga, Ambatovory ; 18°54’S, 47°42’E; III.1883; Dr. Fox 24; K! ex LDS • Centre; 1887; C. M. Le Myre de Vilers s.n.; P [ P00094474 ] ! • Analamanga, Ambohimanga ; 18°45’42”S, 47°33’49”E; 12. VI.1905; C. d’Alleizette s.n.; L [ L1487720 ] ! • Analamanga , environs de Nanisana près de Tananarive; 18°54’S, 47°42’E; 20. I.1906; L. Rotereau s.n.; P [ P06796776 ] ! • Analamanga, Nanisana ; 18°54’S, 47°42’E; I.1906; C. d’Alleizette 977 M; P [ P00334732 ] ! • Vakinankaratra, Manandona ; alt. 1400 m; IV.1912; H. Perrier 8024; P [ P00094576 ] ! • Vakinankaratra, mont Ibity ; 20°04’03”S, 47°00’04”E; alt. 2000 m; II.1921; H. Perrier 13581; P [ P00094578 ] ! • Analamanga, Ambohimanga ; 18°45’42”S, 47°33’49”E; 27.III.1921; R. Decary 302; P [ P00334738 ] ! • Analamanga, Ambohimanga ; 18°45’42”S, 47°33’49”E; IV.1921; R. Decary 52; P [ P00334739 ] ! • Haute Matsiatra, massif d’Andringitra ; alt. 2000 m; II.1923; H. Perrier 14431; P [ P00094579 ] ! • Diana, Ankaizina ; alt. 1500 m; 19.IV.1923; R. Decary 1918; P [ P00334737 ] ! • Diana, Ankaizina ; alt. 1500 m; 19.IV.1923; R. Decary 1936; P [ P00334736 ] ! • Diana, Ankaizina ; 18°54’S, 47°42’E; alt. 1700 m; 19.IV.1923; R. Decary 1997; P [ P00334735 ] ! • Vakinankaratra, entre Ambatolampy et Antsirabe ; alt. 1600 m; II.1927; H. Perrier 17906; P [ P00334733 , P00334734 ] ! • Haute Matsiatra, Andringitra ; 26.II.1938; P. Boiteau 3135; P [ P00692296 , P00692297 ] ! • Haute Matsiatra, au sommet de l’Ambondrombe ; 21°52’30”S, 47°15’37”E; alt. 2000 m; 11.IV.1941; P. Boiteau 4611; P [ P00692437 ] ! • Analamanga, Ambohitantely ; 18°05’S, 47°16’E; 24.II.1945; A. M. Homolle s.n.; P [ P00692274 ]! the four plants on the left are Tylostigma nigrescens Schltr. or Tylostigma perrieri Schltr . • Analamanga, Tampoketsa d’Ankazobe ; 18°13’S, 47°17’E; 7.II.1948; P. Boiteau 6725; TAN ! • Diana , massif de Marivorahona; alt. 2000-2244 m; 18-26.III.1951; H. Humbert et al. 25753; P [ P02115322 plant on the right only, P02115321 , plant on the right only] ! • Alaotra-Mangoro, Ambatosoratra , Atozaka, RN 3; 17°38’30”S, 48°50’00”E; 20.III.1953; ResNat 6055; P [ P00692314 ] ! • Haute Matsiatra, RN 5, Canton Sendrisoa, District Ambalavao ; 27.II.1954; R. Rakoto 6484; P [ P00692315 ] ! • Vakinankaratra, route d’Ambatolampy, Faratsiho ; 19°23’S, 47°16’E; alt. 1800; VIII.1955; J. Bosser 10880; P [ P00692227 ] ! • Vakinankaratra, Ambohimandroro, Ampatolampy ; XI.1955; J. Bosser 9206; TAN ! • Vakinankaratra, Nanokely, Ankaratra ; 19°32’S, 47°03’E; alt. 2000 m; II.1957; J. Bosser 10878; P [ P00692226 ] ! • Vakinankaratra, Nanokely (district de Faratsiho ); 19°32’S, 47°03’E; 26.II.1960; M. Peltier 1915; P [ P00692290 ] ! • Analamanga , Soavina PK 22 route de Tamatave; 18°52’S, 47°40’E; III.1960; J. Bosser 13532; P [ P00692228 ] ! • Amoron’i Mania, Fiadanana, Ilaka , Ambositra ; 20°34’30”S, 46°57’30”E; 20.III.1960; M. Peltier 2149; P [ P00692292 ] ! • Analamanga , vallée de Soavina, PK 23 route de Tamatave; II.1961; J. Bosser 14863; TAN ! • Vakinankaratra, Manjakatompo ; 19°21’25”S, 47°18’28”E; III.1961; J. Bosser 15024; P [ P00692229 ] ! • Analamanga, lake Mantasoa ; 19°00’45”S, 47°50’17”E; IX.1962; J. Bosser 16144; P [ P00692230 ] ! • Vakinankaratra, Nanokely, Ankaratra ; 19°32’S, 47°03’E; II.1963; J. Bosser 17573; P [ P00692241 ] ! • Route de Majunga ; III.1963; J. Bosser 16783; P [ P00692235 ] ! • Vakinankaratra, route d’Ambatolampy ; 19°23’S, 47°16’E; III.1963; J. Bosser 16797; P [ P00692236 ] ! • Vakinankaratra, route Ambatolampy-Faratsiho ; II.1964; J. Bosser 19264; P [ P00692246 , P00692247 ] ! • Haute Matsiatra, sentier du pic Boby, Andringitra ; 22°11’S, 46°53’E; IV.1964; J. Bosser 19478; P [ P00692248 , P00692249 ] ! • Haute Matsiatra, Andringitra ; 22°13’S, 46°55’E; IV.1964; J. Bosser 19492; P [ P00692251 ] ! • Haute Matsiatra, Andringitra ; IV.1964; J. Bosser 19506; P [ P00692252 , P00692253 ] ! • Vakinankaratra, Col des Tapias, 45 km avant Ambositra ; 20°14’34”S, 47°06’04”E; IV.1964; J. Bosser 19598; P [ P00692259 ] ! • sine loc.; 28.III.1969; anonym; HEID [ HEID250340 ] ! • Vakinankaratra, Mt. Ibity western slope; 20°05’44”S, 47°00’12”E; alt. 1900 m; III.1972; G. Cremers 2037; TAN ! • Vakinankaratra, south of Antsirabe, Mt. Ibity ; 20°10’S, 47°03’E; alt. 1300-1800 m; III.1985; L. C. Barnett et al. 491; TAN!, MO [ MO3022638 ] ! • Haute Matsiatra, Andringitra Forest Reserve, along path to Pic Boby ; 22°11’S, 46°55’E; alt. 1900-2050 m; III.1989; P. Goldblatt et al. 8964; P [ P00692435 ]!, MO [ MO4314431 ]!, TAN!, WAG [ WAG.1130546] ! • Vakinankaratra, Ankaratra Massif , W of Ambatolampy; 19°20’S, 47°16’E; alt. 2350 m; III.1989; P. Goldblatt et al. 9012; MO [ MO4314448 ]!, TAN ! • Amoron’i Mania, on hillside near Talavina, PK 204 from Antananarivo to Ambositra ; 20°10’42”S, 47°05’24”E; alt. 1230- 1330 m; V.1993; C. H. Jongkind et al. 829; K!, MO [ MO3022616 ]!, P [ P00692179 ]!, TAN ! • Vakinankaratra, Col Tapia , 36 km S of Antsirabe; 20°10’41”S, 47°05’16”E; alt. 1400 m; IV.1995; D. DuPuy et al. M906 ; K!, P [ P00059605 ]!, MO!, WAG!, TAN ! • Analamanga, Tampoketsa d’Ankazobe ; 17°52’07”S, 47°03’39”E; 18.III.1999; J. N. Labat 2951; P [ P00160016 , P00160017 ]!, G!, K!, MO!, TAN ! • Between Antananarivo and Ambositra, Tapia forest ; 2000; J. Hermans 4393; K ! • Vakinankaratra, between Antsirabe and Ambositra , on RN7, about 3 km before Col Tapia ; alt. 1440 m; IV.2001; J. Hermans 5251; K ! • Vakinankaratra, between Antsirabe and Ambositra , on RN7, about at Col Tapia ; 20°14’25”S, 47°06’12”E; alt. 1740 m; V.2001; J. Hermans 5205; K! with spirit • Amoron’i Mania, Ambositra, Ivato , road to Antoetra ; 20°45’43”S, 47°19’31”E; alt. 1701 m; 25. I.2007; A. Sieder FS 4188 and J. Hermans 8086; WU [ WU0063773 , spirit material] ! • Amoron’i Mania, Ambatofinandrahana , 25 km W of Itremo village; 20°34’12”S, 46°34’55”E; alt. 1647 m; 21.II.2010; L. Rajavelona et al. RJL148; K [ K664548 ]!, TAN ! • Amoron’i Mania, Antoetra , on inselberg; 20°46’27”S, 47°19’16”E; II.2015; alt. 1676 m; A. & C. Sieder et al. 6801; WU! spirit material • N 4, 126 km north of Tana , inselberg; II.2017, A. & C. Sieder et al. 7309; WU! flower in alcohol • Vakinankaratra, between Antsirabe and Ambositra , on RN7, Col Tapia ; IV.2018; J. Hermans 8241; K ! • Analamanga , Andakana RN 4; 18°15’58”S, 47°10’51”E; 19.III.2019; alt. 1461 m; A. & C. Sieder et al. 7792; WU ! • Analamanga, RN 4, c. 12 km after Ankazobe ; alt. 1461 m; III.2019; Sieder A. & C. et al., L 7787; WU !.

NOTES

A very widespread species, with a variable spur length. Any differences between Benthamia rostrata and B. perularioides do not hold when a large number of specimens are examined. Moreover, there are no distinct distribution zones as suggested by Perrier ( Perrier 1939: 24, 25), with Benthamia perularioides north of Ankaratra and Benthamia rostrata south of Ankaratra. This species was also often misidentified as Benthamia bathieana , which added to the confusion.

Benthamia perularioides and B. rostrata were described in the same publication by Schlechter. The rules of nomenclature allow a choice of which name to prioritise. We have chosen B. rostrata because this name is more widely used. The type indicated by Schlechter for his Platanthera madagascariensis is “Perrier de la Bathie XXI, β“. He copied this on specimen P00094574 which has handwritten XXI and B together with the number 8101. Schlechter (1924: 33) gave “ H. Perrier 8101 (XXI B)” when he coined the name Benthamia rostrata . The specimen P00094574 was thus sent to Berlin and returned to Paris, so there is no ambiguity that it is the holotype. For Benthamia perularioides Schlechter cited Perrier 13523 for the type, but there are in P two specimens with this collection number. We have chosenP00094567 as lectotype because Perrier indicated on it that it was sent to Schlechter in April 1921.

This species, which has an elongated spur, is different from the type of the genus Benthamia and other species with a scrotiform or short spur. It is perhaps misplaced in Benthamia . As a matter of fact, specimens identified as Benthamia perularioides in ( Ngugi et al. 2020) were found to be embedded in Cynorkis .

At the beginning of the flowering time the spur is enveloped by the bracts, as is also observed in some African Habenaria .

See also: Schlechter (1930: t.12 n°45, as Benthamia perularioides ), Perrier (1939: 24, as Benthamia perularioides ), Perrier (1939: 25), Cribb & Hermans (2009: 42, as Benthamia perularioides ), Cribb & Hermans (2009: 43), Bosser & Lecoufle (2011: 180), Hervouet (2018: 172).

DESCRIPTION

Erect slender terrestrial herb, 22-70 cm tall. Tubers 4-11, clustered, fusiform, slender and white, 5-8 mm in diameter, 20-60 mm long, roots up to 8, wiry, white, 1-2 mm in diameter. Stem 2-4 mm in diameter, with the base covered by sheaths 25-30 mm long, with above slightly fleshy leaves and higher up 7-10 lanceolate sheaths, gradually turning into floral bracts. Leaves 2-3, more or less narrowly oblong, 7-20 × 1.5- 4 cm, shortly acuminate or mucronate. Rachis rigid, erect, 16-25 × 1.2 cm, densely many-flowered, somewhat unilateral with 30-50 flowers. Floral bracts lanceolate, very acuminate, erectly spreading, 5-15 × 1.5-3 mm, embedding the ovary, the lower ones longer than the ovary. Ovary twisted, 5-10 mm long, diameter 0.6-1.6 mm, the basal part fused to the base of the floral bract. Flowers resupinate, c. 7.5 mm and 4 mm deep, olive green turning yellowish; sepals narrowly oblong, obtuse, slightly navicular, the dorsal obscurely 3-veined, erect, 1.8-3.2 × 0.7-1.6 mm, the laterals single-veined, spreading, 2.3-4 × 0.7-1.9 mm; petals narrowly oval-obtuse, obscurely 2-veined, a little expanded at the anterior margin towards the base, 1.7-3.2 × 0.9-1.6 mm, forming a hood with the dorsal sepal; lip a little longer than the sepals, 2.8-4 × 1-2.3 mm, rhomboid in outline, tri-lobed, sometimes geniculate between the spur and the lobes, the central lobe tongue-shaped with apex curving up, obtuse, 1.5 × 0.5 mm, the lateral lobes triangular, obtuse, 0.5 × 0.7 mm; spur subcylindrical, trumpet-shaped at first then becoming thinner, pendent or trapped into the bract, narrowed from the base to the obtuse apex, whitish green, as long as the sepals, 2.3-6 × 0.3-0.6 mm. Anther not apiculate, suborbicular, 1-2.2 × 0.8-1.3 mm, with two distinct chambers; auricles very rounded, thick, almost a quarter the length of the anther; lateral lobes of the rostellum obsolete, the middle one obtuse, pointing backwards. Sweetly scented in the evening.

Figures

FIG. 87. — Benthamia rostrata Schltr.: Mount Ibity, Madagascar, 1 April 2018. Photograph by Jean-Michel Hervouet.

FIG. 88. — Distribution map of Benthamia rostrata Schltr.