Two new species of the genus Benthamia A. Rich. (Orchidaceae) from Madagascar, B. boiteaui Hervouet, sp. nov. and B. bosseri Hervouet, sp. nov. Jean-Michel HERVOUET HDR, Société française d’Orchidophilie (SFO, French Orchid Society), 61 rue du Lieutenant Ricard, F-78400 Chatou (France) jmhervouet@free.fr Pascal DESCOURVIÈRES UMR 7207 CNRS-MNHN-UPMC, Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements, 57 rue Cuvier, CP 48, F-75231, Paris cedex 05 (France) pascal.descourvieres@neuf.fr Félicitée REJO FIENENA Jaona RANAIVO Centre national de Recherche en Environnement (CNRE), Boîte postale 1739 Fiadanana Antananarivo 101 (Madagascar) ranaivo-jaona@yahoo.fr Hervouet J.-M., Descourvières P., Rejo Fienena F. & Ranaivo J. 2014. — Two new species of the genus Benthamia A. Rich. (Orchidaceae) from Madagascar, B. boiteaui Hervouet, sp. nov. and B. bosseri Hervouet, sp. nov.. Adansonia, sér. 3, 36 (2): 209-219. http://dx.doi. org/10.5252/a2014n2a4 KEY WORDS Orchidaceae, Benthamia, Madagascar, Ambondrombe, Andringitra, Ranomafana, new species. ABSTRACT Two new species of Benthamia A. Rich. (Orchidaceae) from Madagascar, B. boiteaui Hervouet, sp. nov. and B. bosseri Hervouet, sp. nov., are described. Both have been found at the summit of Ambondrombe (Haute Matsiatra region, near Ambalavao), and also, for B. boiteaui Hervouet, sp. nov. in the Ranomafana national park, and for B. bosseri Hervouet, sp. nov. in the Andringitra massif. The two species are represented in the Paris herbarium at the Muséum national d’Histoire naturelle (MNHN) by specimens collected in April 1941 by Pierre Boiteau and more recently, for B. boiteaui Hervouet, sp. nov. by specimens at K, MO and TAN, and for B. bosseri Hervouet, sp. nov., by specimens collected by Jean Bosser in April 1964. With linear leaves and an elliptic dorsal sepal, B. boiteaui Hervouet, sp. nov. can easily be distinguished from other Benthamia with white flowers. The non resupinated, drooping flowers and the arching spike of B. bosseri Hervouet, sp. nov. are very distinctive too. ADANSONIA, sér. 3 • 2014 • 36 (2) © Publications Scientifiques du Muséum national d’Histoire naturelle, Paris. www.adansonia.com 209 Hervouet J.-M. et al. MOTS CLÉS Orchidaceae, Benthamia, Madagascar, Ambondrombe, Andringitra, Ranomafana, espèces nouvelles. RÉSUMÉ Deux nouvelles espèces du genre Benthamia A. Rich. (Orchidaceae) à Madagascar, B. boiteaui Hervouet, sp. nov. et B. bosseri Hervouet, sp. nov. Deux nouvelles espèces de Benthamia A. Rich. (Orchidaceae) de Madagascar, B. boiteaui Hervouet, sp. nov. et B. bosseri Hervouet, sp. nov., sont décrites. Les deux ont été trouvées au sommet de l’Ambondrombe (région Haute Matsiatra, près d’Ambalavao), ainsi que, pour B. boiteaui Hervouet, sp. nov., dans le Parc national de Ranomafana, et pour B. bosseri Hervouet, sp. nov. dans le massif de l’Andringitra. Ces espèces correspondent à des spécimens anciens conservés au Muséum national d’Histoire naturelle (MNHN) et collectés en avril 1941 par Pierre Boiteau ainsi que plus récemment, pour B. boiteaui Hervouet, sp. nov., à des spécimens conservés à K, MO et TAN, et pour B. bosseri Hervouet, sp. nov. à des spécimens collectés par Jean Bosser en avril 1964. Avec ses feuilles linéaires et son sépale dorsal elliptique B. boiteaui Hervouet, sp. nov. se distingue facilement de tous les Benthamia à fleurs blanches connus à ce jour. Les fleurs non résupinées et pendantes, ainsi que l’épi arqué de B. bosseri Hervouet, sp. nov. en font aussi une espèce très distincte. INTRODUCTION The genus Benthamia A. Rich. was first described by Achille Richard in 1828, the name being a tribute to George Bentham, the British botanist. It was created to accommodate the already existing Satyrium latifolium Thouars (today Benthamia chlorantha (K. Sprengel) Garay & Romero), and Satyrium spirale Thouars, which is henceforth Benthamia spiralis (Thouars) A. Rich. The genus is characterized by the following features: terrestrial or rarely (two species) epiphytic herbs, with 2 to 7 ovoid tubers. Stem with only sheaths or 1-2 basal leaves or 2-5 cauline leaves. Inflorescence terminal, with a lax to dense spike, cylindrical, more or less secund (i.e. arranged on one side of the axis only), or secund. Flowers small (less than 1 cm), white, whitish, yellow, yellowish, green, greenish or reddish orange. Lip entire or, more often, trilobed, with a short spur at the base, generally scrotiform, globular or saccate, but also cylindrical or clavate. Column with parallel anther locules. Viscidia flat, oval or elliptic. Staminodes well developed, subspathulate or falcate. Rostellum small, trilobed or tridentate. 210 Stigmas always very short. Pollinia 2. A more detailed description of the gynostemium based on B. spiralis (Thouars) A. Rich. and B. cinnabarina (Rolfe) H. Perrier is given in Szlachetko (2000). The last comprehensive treatment of the genus with full description of species dates back to Perrier’s work in 1939. In 2009 Cribb and Hermans published a key and an updated list with short descriptions, in their field guide to the orchids of Madagascar. The genus nowadays comprises 30 species and six sub-species, all endemic from Madagascar and the Mascarene Islands, except Benthamia drummondii (Linder & Williamson) Szlachetko & Rutkowski in Zimbabwe, originally described as the only member of the genus Oligophyton Linder. In the list published by Cribb and Hermans we exclude B. leandriana H. Perrier, renamed Cynorkis tryphioides var. leandriana by Jean Bosser in 1969. We also suspect B. bathieana Schltr. and B. rostrata Schltr. to be one and the same species, and B. exilis Schltr. to be a Cynorkis, for its similarity to C. micrantha (Frappier) Schltr. in la Réunion. Except the Zimbabwean species, the last three new species of Benthamia were described by ADANSONIA, sér. 3 • 2014 • 36 (2) Two new species of Benthamia A. Rich. from Madagascar H. Perrier in 1951. A revision of the whole genus, along with genetic studies to verify its monophyletic origin, is much needed. A number of specimens at the Muséum national d’Histoire naturelle in Paris (MNHN) remain undetermined and are potential new species. We describe hereafter two of them, because of their prominent features that easily allow to tell them apart from other species, and because they both grow on the Ambondrombe mountain in the Haute Matsiatra region, near Ambalavao. Moreover they have been seen and photographed in the wild, in their locus classicus, during an expedition of the French Orchid Society (SFO) in March 2009 (Hervouet & Guérin 2011). The two species were first collected by Pierre Boiteau near the summit of Ambondrombe in April 1941. From his collections he described the following year, in the Bulletin de l’Académie Malgache, three new species of orchids: Physoceras australe Boiteau and Cynorkis ambondrombensis Boiteau, collected on Ambondrombe, and Bulbophyllum ceriodorum Boiteau from Mount Tsitondroina. Physoceras australe was seen again in 2009 but Cynorkis ambondrombensis still awaits rediscovery, it is said to be one of the most beautiful species of Cynorkis in Madagascar. For two species of Benthamia that he could not determine, Pierre Boiteau indicated on the herbarium sheets that they were potential new species and proposed possible relatives in the genus. It is these two species that we describe in this paper. In 1964, the second species was also collected by Jean Bosser in the Andringitra massif, but not described, though again considered as a new species (Jean Bosser, pers. comm.). In 1995, the first species was collected in Ranomafana national park (Phillip Cribb pers. comm.) and once again considered to be a new species. MATERIAL AND METHODS We worked on the MNHN specimens listed in the next sections. Except for the collection by Jean Bosser, they are all labelled as originating from the “Herbier du jardin botanique de ADANSONIA, sér. 3 • 2014 • 36 (2) Tananarive”, i.e., the Tsimbazaza herbarium at Antananarivo. The collector is not mentioned but Lucile Allorge, Pierre Boiteau’s daughter and also an outstanding botanist, formally identified her father’s handwriting on the specimens. The Tsimbazaza collections at Antananarivo (TAN) have been extensively searched by the third author, but none of the two species have been located there among the 52 specimens of Benthamia, or among the close genera. Flowers in spirit have not been located either. The drawings were done by Alain Jouy after the type specimens, with the help of colour photographs taken in the wild in March 2009. No voucher was collected in 2009 and no fresh material dissected, so the descriptions are based here on rehydrated flowers of the original Boiteau and Bosser specimens, which precluded an accurate description of the very small and somewhat damaged columns. SYSTEMATICS BENTHAMIA BOITEAUI HERVOUET, SP. NOV. The first species is so far known only from Ambondrombe and is represented at MNHN by three specimens with a total of six individuals. It has white flowers with a green mouth of the spur. Boiteau wrote that it was either a new species or a variety of B. melanopoda Schltr. The key published by Cribb and Hermans leads, due to a short spur, a 3-lobed lip, more than one linear leaf and white flowers, to Benthamia madagascariensis (Rolfe) Schltr., but the sepals of the latter are linear, which is clearly not the case here, and the side lobes of the 3-lobed lip are not acute as in the present species. If we discard the color we alternatively get to B. melanopoda, but this species has side lobes of the lip much longer than the mid lobe, or we arrive at species with sepals less than 4 mm, moreover with brownish or greenish flowers. Actually B. madagascariensis (Rolfe) Schltr., B. nivea Schltr. and B. herminioides Schltr. were so far the only species known with white flowers. For these different reasons we clearly have here a new species with no close relative. 211 Hervouet J.-M. et al. A B D C FIG. 1. — Benthamia boiteaui Hervouet, sp. nov.: A, habit (after wild specimen); B, flower (Boiteau 4621); C, side view of flower; D, exploded view of perianth. Scale bars: A, 50 mm; B, 2 mm; C, D, 3 mm. Drawing by Alain Jouy. 212 ADANSONIA, sér. 3 • 2014 • 36 (2) Two new species of Benthamia A. Rich. from Madagascar FIG. 2. — Benthamia boiteaui Hervouet, sp. nov.: spike of a wild specimen at the summit of Ambondrombe (9.III.2009). Photograph by Jean-Michel Hervouet. Benthamia boiteaui Hervouet, sp. nov. (Figs 1; 2) Herba terrestris 33-38 cm alta, Benthamiae melanopodae Schltr. similis, sed floribus albis, non galbinis differt. Benthamiae madagascariensi (Rolfe) Schltr. habitu vicina, sed ab forma florum distat, cum sepalo dorsalo elliptico, non lineare. Benthamiae herminioide floribus latioribus differt. TYPUS. — Madagascar. Fianarantsoa Province, Haute Matsiatra Region, Near summit of Ambondrombe, among wet rocks, 1900 m [approximate coordinates: 21°52’29”S, 47°15’37”E], fl., 11.IV.1941, Boiteau 4621 (holo-, P[P00692438!, 2 individuals]). PARATYPES. — Madagascar. Fianarantsoa Province, Haute Matsiatra Region, Ambondrombe, mossy forest around 1700 m, fl., 11.IV.1941, Boiteau 4637 (P[P00692439!, 1 individual; P00692440!, 3 individuals]); Ranomafana National Park, vicinity of Ampasina, 1150 m [approximate coordinates 21°11’S, 47°25’E], fl., 10.III.1995, Turk, Randrianasolo & Rajoma 722 (K!, MO, TAN). ADANSONIA, sér. 3 • 2014 • 36 (2) Description Terrestrial herb with erect, cylindrical, and green stems 33-38 cm long, 0.2 cm in diameter. One or two sheaths at the stem base, 2 to 3 leaves in the lower ⅔ of the stem length. Leaves sheathing, thin, flexible, linear, acute, 50-130 × 5-8 mm. One or two sterile bracts in upper part of stem, linear, acute, 15-30 × 2-3 mm. Inflorescence terminal, erect, 17-33 flowered. Rachis 5-8 cm long. Bracts acicular, longer than ovary, 6-11 × 2 mm. Flowers white, resupinate. Dorsal sepal elliptic, obtuse with slightly concave rounded apex, 3-5 mm long, 2-3 mm wide. Lateral sepals elliptic, 4-5 × 2-3 mm, with one visible vein, slightly keeled dorsally, slightly ventrally concave, apex rounded or subacute, margin smooth. Petals elliptic, 3-4 × 2 mm, with one visible vein, apex rounded or subacute, margin smooth or slightly irregular. Lip 3-lobed, 3-4 × 2.5-3.0 mm, side 213 Hervouet J.-M. et al. lobes acute, 0.5 mm, middle lobe slightly inflated, 1.0-1.3 mm long, spur green, very short and obtuse, touching the ovary. Ovary 6-7 mm long, 2-3 mm in diameter. Pollinia 2. Habitat and distribution This species seems restricted to high altitude areas with patches of prairies among granite or gneiss outcrops, interspersed with ericoid shrubs and small trees, or mossy forest. It is known so far only from the higher altitudes of the Ambondrombe Mountain (Haute Matsiatra region) from 1700 to 1900 m, on wet rocks in full sun or in more shaded areas in the mossy forest. We give hereafter a translation of Boiteau’s own description of the habitat: “The visited region is especially interesting because it has been preserved by the bad reputation of Ambondrombe. This vegetation is mostly composed of mossy forest with herbaceous understorey, typical of middle altitudes. From 1800 m on, on parts with poorer soil, lichen-rich forest gradually settles, then come ericaceous shrubs on rocks in the summit. On western slopes, today nearly fully barren, once was a typical woodland formation with many deciduous trees. Some remnants intergrading towards this kind of vegetation can still be found, with austral affinities such as the Proteaceae (Faurea forficuloides [sic]), mixed with typically indo-malayan plants such as Myrica: M. dentulata. If the western slopes woodlands have nearly disappeared today, being the most flammable, the mossy forest with herbaceous understorey is also gradually receding. It is first replaced by the savoka with Philippia scrub, then very rapidly by grassland, as species-poor as on the plateaux”. Phenology Benthamia boiteaui Hervouet, sp. nov. flowers in March and April, with Benthamia herminioides Schltr. In Ambondrombe in the same area the terrestrial Disa brevicornis (Lindley) Bolus and the epiphytic Eulophiella galbana (Ridley) Bosser & Morat flower in January (Guérin & Hervouet 2013), Jumellea ibityana Schltr. flowers in March (Guérin & Hervouet 2011). Etymology This species is dedicated to Pierre Boiteau (19111980), collector of the type. He was a professor, botanist and director of the Tsimbazaza botanical and zoological garden in Antananarivo, from 1935 to 1947. As a whole he produced about 700 articles and ten books. During the month of April 1941, he did a 10-day field survey of Betsileo country, Mount Tsitondroina and Mount Ambondrombe. More than 700 herbarium specimens and 250 living plants were brought back to Tsimbazaza. Conservation The species is known only from Ranomafana National Park and from the top of Ambondrombe. Being considered as the sacred mountain of the Dead by the Betsileo people, this latter site is so far relatively safe, and is still covered by dense tropical forests. However there is no official protection status of this area. In a 4-day survey in the forest around the mountain in 2011, we chanced upon an illegal settler who slashed the forest to create a rice field. Host of more than 100 species of orchids, the Ambondrombe massif is an important link between north and south along the eastern KEY TO SPECIES OF BENTHAMIA A.RICH. WITH WHITE FLOWERS If we follow the Cribb & Hermans (2009) key, all these species first share the following features: spur very short, lip 3-lobed, leaves 2 or more. Then they can be identified with the following key: 1. Leaves linear ............................................................................................................... 2 — Leaves oblong-lanceolate, elliptic-lanceolate or lanceolate .......................................... 3 2. Dorsal sepal linear .................................................... B. madagascariensis (Rolfe) Schltr. — Dorsal sepal elliptic ........................................................ B. boiteaui Hervouet, sp. nov. 3. Lip 2-3 mm ............................................................................... B. herminioides Schltr. — Lip 8-9 mm .......................................................................................... B. nivea Schltr. 214 ADANSONIA, sér. 3 • 2014 • 36 (2) Two new species of Benthamia A. Rich. from Madagascar B A D C FIG. 3. — Benthamia bosseri Hervouet, sp. nov.: A, habit (after wild specimen); B, flower (Boiteau 4634); C, side view of flower; D, exploded view of perianth. Scale bars: A, 50 mm; B, 3 mm; C, 2 mm; D, 4 mm. Drawing by Alain Jouy. ADANSONIA, sér. 3 • 2014 • 36 (2) 215 Hervouet J.-M. et al. FIG. 4. — Benthamia bosseri Hervouet, sp. nov.: typical arched spike with pendent second flowers. Summit of Ambondrombe (9.III.2009). Photograph by Jean-Michel Hervouet. Malagasy escarpment and would deserve a specific protection status. For the time being we quote the species as Near Threatened (NT), for its very small number of known locations. BENTHAMIA BOSSERI HERVOUET, SP. NOV. The second species is represented at MNHN by five specimens and eleven plants, all from Ambondrombe except one herbarium sheet with three plants collected in Andringitra by Jean Bosser in April 1964. This species has two outstanding features: the yellow flowers are non-resupinate (this is so far unique in Benthamia) and secund, the spike is rather strongly and rigidly arching so that, in the wild, the flowers are facing downwards. Pierre Boiteau labelled the specimens “Benthamia verecunda?”, but B. verecunda flowers are green216 ish and resupinate, the leaves are broader and the spike is not arching. The combination of short spur, 3-lobed lip, more than one linear leaf, and flowers yellow with side lobes of the lip shorter than the mid lobe leads in the key to B. procera Schltr., the latter with a shorter ovary, a straight and less unilateral spike, and resupinate flowers. Jean Bosser gave us the following description: “Épi unilatéral, un peu courbé, fleurs inversées, bractées, ovaires et sépales lavés de rougeâtre. Pétales et labelle jaunâtres”, which is: “unilateral spike, slightly arching, flowers non-resupinate, bracts, ovary and sepals reddishly tinted. Petals and lip yellowish”. In fact the spike is often strongly arching, so as to form a semi-circular arch, e.g. the plant on the left on Bosser’s specimens, the other two being obviously somewhat artificially straightened during mounting. ADANSONIA, sér. 3 • 2014 • 36 (2) Two new species of Benthamia A. Rich. from Madagascar FIG. 5. — Vegetation and granite outcrops near the summit of Ambondrombe (9.III.2009). Photograph by Jean-Michel Hervouet. Benthamia bosseri Hervouet, sp. nov. (Figs 3, 4; Table 1) Herba terrestris 20 cm usque ad 70 cm alta, Benthamiae cinnabarinae (Rolfe) H. Perrier et Benthamiae verecundae Schltr. vicina, sed rachide valde arcuata et labello non resupinato praecipue differt. Quoque Benthamiae procerae Schltr. similis, sed non solum labello non resupinato differt, sed etiam forma calcaris, disciformi et non dilatata ad apicem. TYPUS. — Madagascar. Fianarantsoa Province, Haute Matsiatra Region, Ambondrombe, among wet rocks, 1700 m, fl., 11.IV.1941, Boiteau 4634 (holo-, P[P00692301!] ; iso-, P[P00692302!, 3 individuals]). PARATYPES. — Madagascar. Fianarantsoa Province, Haute Matsiatra Region, Ambondrombe, among wet rocks, 1700 m, fl., 11 IV 1941, Boiteau 4634 (P[P00692302!, 3 individuals]); marsh with mosses near summit of Ambondrombe, 1900 m, fl., 11.IV.1941, Boiteau 4598 (P[P00692299!, 2 individuals], P[P00692300!, 2 individuals]); Andringitra National Park, among vegetation in altitude [approximate coordinates: 22°13’22”S, 46°55’45”E], fl., IV.1964, Bosser 19648 (P[P00692265!, 3 individuals]). ADANSONIA, sér. 3 • 2014 • 36 (2) Description Terrestrial herb with erect cylindrical stems 21-71 cm long, green or purple (on same plant), 2-5 mm in diameter. One or two sheaths at base of the stem, 2 to 3 leaves in the lower part of the stem. Leaves sheathing at their base, thin, flexible, linear, acute, 50-140 × 5-10 mm. Two to three sterile bracts in upper part of stem, linear, acute, 13-25 × 2-3 mm. Inflorescence terminal, arching, 20-50 flowered. Rachis 7-19 cm long. Floral bracts decurrent, acicular, reddish, as long as ovary + flower, 7-12 × 2 mm. Flowers secund, yellow and reddish, not resupinate, drooping downward, seemingly semipeloric. Sepals similar, reddish, linear, concave, 3-3.5 × 1 mm, with a central vein, dorsally slightly keeled. Petals linear, yellow, similar to sepals but slightly narrower, slightly thickened at apex, 3-3.5 × 0.8-1 mm. Lip 3-lobed (a feature hardly visible on rehydrated material), 3-4 × 0.8-1 mm, mid lobe thickened at apex, 1 mm long, side lobes slightly 217 Hervouet J.-M. et al. TABLE 1. — Main differences between Benthamia bosseri, Hervouet sp. nov. and close species. Flowers B. bosseri sp. nov. yellow, secund, not resupinate yellow, in a spiral B. cinnabarina resupinate yellowish, secund B. procera resupinate greenish, secund B. verecunda resupinate spike arcuate, dense erect intermediate scrotiform erect intermediate purse shaped nearly erect dense shorter than mid lobe, thickened on fresh material, flat and folded on lip when dried, spur very short (1 mm), somewhat discoid. Ovary greenish or reddish, 3 mm long (fresh flower) to 10 mm (fruit), 1-2 mm in diameter. Column terete, very short (0.9-1 mm). Pollinia 2. Habitat and distribution This species was found growing in the same habitat as B. boiteaui Hervouet, sp. nov. on Ambondrombe massif (Fig. 5), but has also been collected in Andringitra National Park (about 60 km from Ambondrombe in the south-west direction) with a similar habitat on large prairies and rocks. It was still observed in both locations during the SFO field trip in 2009, so it is probably not very rare. Etymology This species is dedicated to Jean Bosser, who collected it in the Andringitra massif and advised us to publish its description. Jean Bosser, from the year 1960 on, described, mostly in this journal, around 120 new species of orchids from the MadagascarMascarene area and was thus very instrumental in the advancement of our current knowledge of Orchidaceae in this region. Jean Bosser sadly passed away on 6th December 2013, during the review process of this paper. Conservation This species is probably not presently endangered as it grows both in Ambondrombe and in Andringitra National Park. However due to its little number of locations we give it the IUCN quotation NT (Near Threatened). 218 spur discoid almost globular leaves linear fl. period March-April linear lanceolate linear lanceolate lanceolate February-May Oct.-Dec. April Acknowledgements We kindly thank Alain Jouy for his care in drawing the plants and his patience with us, and Thierry Pain who corrected and improved greatly the latin diagnosis. We owe a lot to the generous hospitality of MNHN in the herbarium, namely Marc Pignal and Germinal Rouhan for help, technical discussions and advice, Lucile Allorge for kindly providing key data on her father Pierre Boiteau, and Thierry Deroin for his useful guidance and review of the article. We are also indebted to France Rakotondrainibe for her suggestions on the manuscript, and Johan Hermans for his judicious advice and remarks and generally speaking for fruitful and open exchanges of data. We warmly thank Phillip Cribb for kindly reviewing the paper and sending us his own drawings and photographs of the Ranomafana specimen of Benthamia boiteaui Hervouet, sp. nov. Lastly we duly thank Jean-Claude Guérin, president of the SFO Poitou-Charentes-Vendée, for his organisation of a number of SFO field trips to Madagascar. REFERENCES BOITEAU P. 1942. — Plantes nouvelles de Madagascar. Bulletin de l’Académie malgache XXIV: 88-90. BOSSER J. & LECOUFLE M. 2011. — Les orchidées de Madagascar. Biotope, Collection Parthénope, 496 p. CRIBB P. & HERMANS J. 2009. — Field Guide to the Orchids of Madagascar. Royal Botanical Gardens, Kew, 456 p. DU PUY D., CRIBB P., BOSSER J., HERMANS C. & HERMANS J. 1999. — The Orchids of Madagascar. Royal Botanic Gardens, Kew, 376 p. GUÉRIN J.-C. & HERVOUET J.-M. 2011. — Neuvième voyage à Madagascar, Ambondrombe, la montagne des morts. L’Orchidophile 188: 87-101. ADANSONIA, sér. 3 • 2014 • 36 (2) Two new species of Benthamia A. Rich. from Madagascar GUÉRIN J.-C. & HERVOUET J.-M. 2013. — Dixième voyage à Madagascar : Ambondrombe, le pic Boby, le pic Ivohibe et le corridor de Vondrozo. L’Orchidophile 199: 319-334. HERMANS J., HERMANS C., DU PUY D., CRIBB P. J. & BOSSER J. 2007. — Orchids of Madagascar. Second Edition, Royal Botanic Gardens, Kew, 398 p. HERVOUET J.-M & GUÉRIN J.-C. 2011. — Madagascar, the orchids of Ambondrombe, the mountain of the Dead. Proceedings of the 20th World Orchid Conference, 13-20 November 2011. Singapore Botanic Gardens, Singapore: 399-404. IUCN 2012. — IUCN Red List Categories and Criteria: version 3.1. Second edition. Gland, Switzerland and Cambridge, UK. IUCN. iv+32 pp. PERRIER DE LA BÂTHIE H. 1934. — Le genre Benthamia (Orchidées). Bulletin de la Société botanique de France 81: 25-38. PERRIER DE LA BÂTHIE H. 1939. — Orchidaceae, volume 1, in HUMBERT H. (ed.), Flore de Madagascar et des Comores, 49. Antananarivo, Madagascar: 16-40. PERRIER DE LA BÂTHIE H. 1951. — Orchidées de Madagascar et des Comores. Nouvelles observations. Notulae Systematicae 14 (2): 138-165. RICHARD A. 1828. — Monographie des Orchidées des Îles de France et Bourbon. Imprimerie de J. Tastu, Paris: 43-44. SZLACHETKO D. L. 2000. — Gynostema Orchidalium I. Acta Botanica Fennica 169: 129, 130. Submitted on 28 June 2013; accepted on 3rd February 2014; published on 26 December 2014. ADANSONIA, sér. 3 • 2014 • 36 (2) 219