Cyrtorchis arcuata subsp. arcuata

Azandi, Laura, Stevart, Tariq, Sonké, Bonaventure, Simo-Droissart, Murielle, Avana, Marie-Louise & Droissart, Vincent, 2016, Synoptic revision of the genus Cyrtorchis Schltr. (Angraecinae, Orchidaceae) in Central Africa, with the description of a new species restricted to submontane vegetation, Phytotaxa 267 (3), pp. 165-186 : 168-172

Cyrtorchis arcuata subsp. arcuata .

Heterotypic synonyms: Listrostachys sedeni Reichenbach (1878a: 138) . Angraecum sedenii (Rchb.f.) Nicholson (1884: 79) . Angorchis sedenii (Rchb.f.) Kuntze (1891: 652) . Cyrtorchis sedenii (Rchb.f.) Schlechter (1918: 132) . Type:— SIERRA LEONE. Mateboi, Sanda Tenraran Chiefdom, 7 June 1951, P.Adames 229 (holotype K!).

Listrostachys obrieniana (Hort.Sand.) Rolfe (1912: 284) . Angraecum obrienianum Sander (1892: 816) , nomen nudum.

Cyrtorchis bracteata Schlechter (1915: 600) . Type:— TANZANIA. Nyassa Hochland, Station Kyimbila, 10 May 1911, A.F.Stolz 715. (holotype B†, isotypes C, WAG, K!, M).

Listrostachys acuminata Rolfe (1897: 154) . Cyrtorchis acuminata (Rolfe) Schlechter (1918: 128) . Type:— PRÍNCIPE. 31 January 1891, A.Henriques s. n. (holotype K!).

Cyrtorchis arcuata subsp. leonensis Summerhayes (1960: 147) . Type:— SIERRA LEONE. Mateboi, Sanda Tenraran Chiefdom, 7 June 1951, P.Adames. 229 (holotype K!).

Cyrtorchis arcuata subsp. variabilis Summerhayes (1960: 148) . Cyrtorchis arcuata var. variabilis (Summerh.) Geerinck (1988: 548) . Type:— TANZANIA. Kiwanda road Muhesa, 24 January 1942, W.M.Moreau 20 (holotype K!).

Additional specimens examined:— SENEGAL. Kagnout , 5 m, 8 July 1982, Vanden Berghen 5387 ( BR) ; ibid., 4 m, 6 June 1983, Vanden Berghen 5669 ( BR) ; Pointe Saint-georges , 4 m, 8 June 1983, Vanden Berghen 5692 ( BR) . GUINEA.

Pita Near Santali, Futa Djallou, 500 m, 11 September 1962, Adames 352 ( WAG). SIERRA LEONE. Batkanu-pendembu area of the north, 27 May 1946, Deighton 4312 (K) ; Njala , 3 June 1946, Deighton 4313 (K) ; Karina , 30 May 1949, Deighton 5058 (K) ; Masingbe ( Kuinke Sanda ), 30 May 1949, Deighton 5059 (K) ; Musaia, 11 April 1951, Deighton 5543 (K). LIBERIA. Ganta , 23 November 1951, Harley 1842 (K) ; Nimba Mts, 800 m, 21 September 1969, Johansson 627 (K). GHANA. Kumasi , July 1947, Andoh 5049 ( P) ; Atacora Mts, Somba country, from Natitingou to Bocorona , 500 m, 21 June 1910, Chevalier 24215 (K) ; Sine loc., 15 September 1906, Farmar 5282 (K) ; Kumasi to Tamale, Mile 69 on roadside tree, 12 November 1953, Westwood 96 (K) ; Acara, 27 September 1954, Westwood 536 (K). NIGERIA. Ribako forest reserve, May 1948, Keay FHI 22899 (K) ; B. Gwari district , R.Tukuruwa on path between Kurmaza Kasa and Kalangai, 20 June 1950, Keay FHI 25886 (K) ; Upper Ogun cattle estate, edge of river near rut house, May 1965, Sanford 863165 (K) ; Zaria Province, Mile 7 on Kaciya to Zonkwa road, 945 m, 21 June 1957, Summerhayes 115 (K). CAMEROON. Ngaoundéré, sur la route de Meiganga (N1), lac Tison, 30 April 2012, Droissart et al. ( Ombrière de Yaoundé ) 3524 ( WAG) ; ibid., 25 April 2013, Droissart et al. ( Ombrière de Yaoundé ) 4300 ( BRLU) ; ibid., 2 May 2009, Simo et al. ( Ombrière de Yaoundé ) 1539 ( BRLU) ; ibid., 8 April 2010, Simo et al. ( Ombrière de Yaoundé ) 2110 ( P, K) ; ibid., 3 May 2011, Simo et al. (Ombrière de Yaoundé) 2761 ( YA, MBG). CENTRAL AFRICAN REPUBLIC. Yalinga , 18 September 1922, Le Testu 4176 ( P) ; Région de la Waka, riv. Ngudjara 15 Km S.E. Moroubas , 11 September 1924, Tisserant 1620 ( P) ; plateau à l’ouest du vill. Gérélenji 50 Km N. Bambari , 2 September 1925, Tisserant 2022 ( BR, P) ; Région de la Ouaka, galerie riv. Balogu près vill. Blaougu , 20 Km N.E. Bambari, 31 August 1925, Tisserant 2023 ( BR, P) ; ibid., près de Ippy, Gbwapala , 8 September 1925, Tisserant 2024 ( P) ; riv. Gbaoro 5 Km S. Bozoum , 28 August 1932, Tisserant 3152 ( P) ; Sine loc., 23 May 1905, Collection Serres du Muséum de Paris 2 ( P). ETHIOPIA. About 10 km. N. of Awasa , 1,750 m, 19 May 1966, de Wilde 11027 (K) ; Gamu-Gofa region: c. 6 km W. of Jinka along the track to Mago National Park , 1,400 m a.s.l., 8 January 1998, Friis et al. 8623 (K) ; Mezan Tefari, Kaffa, 1,350 m, 2 August 1962, Mooney 9214 (K). SÃO TOME AND PRINCIPE. Terreiro Velho , environ 213 m, 8 December 1932, Exell 511 ( BR) ; Bombaim , 400 m, 1 November 1998, Stévart 452 ( BRLU) ; Entre Focinho de Cao et Cisco Mantero, 70 m, February 2002, Stévart 1213 ( BRLU). DEMOCRATIC REPUBLIC OF THE CONGO. Komatimbu , Bilakislaki , 13 April 1934, De Witte 1511 ( BR) ; Tanganjika , 3 May 1935, Schlieben 6474 ( BR) ; Keyberg, près de Lubumbashi, 1,200 m, 13 April 1967, s coll. 12785 (K). UGANDA. Kinangop Aberdare, 2,713 m, April 1938, Glhandler 2397 (K). KENYA. Kijabe, Rift valley , N. W. of Nairobi, 2,073 m, July 1950, Archer 11 (K) ; Chepalungu forest, Sotik district , 1,920 m, February 1931, Gardner 2554 (K) ; 12 km N. of Maralal on road to Baragoi , 2,100 m, 2 June 1979, Gilbert et al. 5436 (K) ; Uasin Gishu District, 2,316 m, 1 May 1932, Harvey 149 (K) ; Mt Elgon , 19 May 1931, Major & Lugard 565 (K) ; Trans-Nzoia district, 1,800 m, 12 September 1984, Mungai 82/84 (K) ; Meru disctrict, 1,432 m, 1950, Schelpe 11 (K) ; Valley, N. E. Mt Elgon, August 1933, Suam 3181 (K). RWANDA. Mayaga , colline Byogi , au NE de Gakoma, 1,400 m, 14 December 1971, Bamps 3268 ( BR). TANZANIA. Sine loc., 4 August 1982, van der Laan 515 ( WAG). ZAMBIA. Mwinilunga, Zambezi Rapids, 6 km N of Kalene hill Mission, 20 February 1975, Williamson & Gassner 2446 (K). MOZAMBIQUE. Maputo, Matutuina, Entre Zitundo o Ponta do oure ao lado pequeno riacho, 28 January 1983, Groenendijk & de Koning 192 ( BR) ; Inhambane, Pomene, ca 6 km from hotel, ca 1 km past aeroport, 24 September 1980, Jansen 7500 ( BR). SWAZILAND. Lubombo district, Lebombo riefs, Muti-Muti , 700 m, 11 February 1994, la Croix 1176 (K). SOUTH AFRICA. plantes du Cap, Glenfilling, 29 December 1831, Drège 4580 C ( P) ; District d’Uitenhage, on the hills by the Coega River , s. d., s. coll. 1117 ( P) ; Cap de Bonne Espérance , s. d., Drège s. n. ( P) ; Natal, Mapunda district, Tugela Valley below Magumbi , 305 m, 4 March 1962, Edwards 2740 (K) ; Sine loc., 600 m, 25 February 1910, Friedman 857 (K) ; Pondoland , April 1890, Gillett s. n. (K) ; Between Seymoun and Alice , 28 November 1928, Hutchinson 1692 (K) ; Natal, Wlapumalo, 10 miles of Things post, Bushveld new Tugela river , 1,219 m, 8 March 1961, Lodd 10185 (K) ; ibid., Ubombo, False Bay Park, 3 February 1970, Ross 2337 (K) ; Letaba district, by side of Ramadiepa river , 853 m, 8 February 1960, Scheepers 900 (K) ; Mpumalanga, Klipkoppie farm, Luneberg area , 27 February 2003, Van Wyk & Nkuna 630 (K) ; Mtunzini, Ngoya , 18 February 1961, Wells & Edwards 53 (K) ; Addo, Uitenhage district , 609 m ; s. d., Zeyher 1117 (K); ibid., January 1940, s. coll. s. n. (K). Somerset East, s. d., s. coll. s. n. (K) .

Additional specimens examined with unspecified country: —Sine loc., November 1886, Herbert Veitch s. n. (K).

Distribution:— According to Govaerts et al. (2016), Cyrtorchis arcuata subsp. arcuata occurs in twenty seven countries ( Senegal, Guinea-Bissau, Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Togo, Benin, Nigeria, São Tomé and Príncipe, Equatorial Guinea, Cameroon, Central African Republic, Ethiopia, Democratic Republic of the Congo, Rwanda, Burundi, Uganda, Kenya, Tanzania, Zambia, Malawi, Mozambique, Zimbabwe, Swaziland and South Africa), although we have not examined any material from Guinea-Bissau, Ivory Coast, Togo, Benin, Equatorial Guinea, Burundi, Malawi and Zimbabwe. Cyrtorchis arcuata subsp. arcuata is thus widely distributed in Sub-Saharan Africa.

Habitat and ecology:— Epiphyte commonly found on the trunks and large branches of large trees ( Perez-Vera 2003) in various vegetation types (forest, savanna) between 4 and 2,713 m elevation. Flowering peak in September.

Notes:—Initially subdivided into five subspecies by Summerhayes (1960), the C. arcuata complex shows many characters of poor taxonomical value. This complex was later revised by Baker (1994) and reduced into two subspecies, viz. C. arcuata subsp arcuata and C. arcuata subsp whytei . Following la Croix & la Croix (1997) and Cribb & la Croix (1998), we adopted the same concept because the two taxa show clear discriminant features (see Table 1). At this stage, morphometric and molecular studies are required to better discriminate other potential distinct taxa among the C. arcuata complex.

Angraecum obrienianum is a nomen made by Sander (1892) in The Gardeners’ Chronicle & Agricultural Gazette. The species was described as “a thick leaved species of the Chailluanum class” and no specimens were mentioned. This taxon received an award of Merit by the RHS in 1912 ( Rolfe 1912) and a painting of the exhibited plant was done. It was then placed in the genus Listrostachys ( Rolfe 1912) , again without citing any specimen. Rolfe commented that it has some affinity with Listrostachys sedenii , now considered as a synonym of Cyrtorchis arcuata . As a consequence, the only known record of Angraecum obrienianum is the painting which clearly represents Cyrtorchis arcuata . We therefore consider it as a synonym of the latter.