Cyrtorchis arcuata subsp. whytei (Rolfe) Summerhayes (1960: 147)

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 : 173

2. Cyrtorchis arcuata subsp. whytei (Rolfe) Summerhayes (1960: 147) . ( Fig. 3F ) Basionym: Listrostachys whytei Rolfe (1898: 155) . Angraecum whytei (Rolfe) De Wildeman (1916: 191) . Cyrtorchis whytei (Rolfe) Schlechter (1918: 133) . Cyrtorchis arcuata var. whytei (Rolfe) Geerinck (1992: 484) . Type:— MALAWI. Mlanje Plateau, November 1895, A.whyte 102 (holotype K!)

Additional specimens examined:— LIBERIA. Montserredo, Boy Scout’s Camp , 5 November 1970, Stoop - Kasteele 253 ( BR) . CAMEROON. Parc National du Mbam et Djérem, Myéré, vers le service de la conservation, 761 m, 28 May 2012, Droissart et al. ( Ombrière de Yaoundé ) 3569 ( YA) ; ibid., Près de la petite chute, 762 m, 5 June 2012, Droissart et al. ( Ombrière de Yaoundé ) 3592 ( BRLU) ; ibid., A 8,7 km SE de Myéré, forêt ripicole à 500 m NW du campement, 775 m, 6 June 2012, Droissart et al. ( Ombrière de Yaoundé ) 3599 ( P, WAG) ; ibid., 12 June 2013, Droissart et al. ( Ombrière de Yaoundé ) 4357 ( BRLU) ; ibid., 10 June 2011, Simo et al. (Ombrière de Yaoundé) 2853 ( BRLU) ibid., 13 June 2011, Simo et al. ( Ombrière de Yaoundé ) 2863 ( BRLU) ; ibid., 17 June 2011, Simo et al. ( Ombrière de Yaoundé ) 2883 ( YA) ; ibid., 21 June 2011, Simo et al. ( Ombrière de Yaoundé ) 2891 ( BRLU, YA) ; ibid., A 9,14 km de Myéré, savane, 847 m, 13 June 2011, Simo et al. ( Ombrière de Yaoundé ) 2862 ( BRLU) . SÃO TOME AND PRINCIPE. Roça Fortunato , 950 m, 14 December 1997, de Oliveira 340 ( BRLU) ; Monte Café , 600 m, 2 December 2002, Primo & Stévart 110 ( BRLU) ; Porto Alegre , 100 m, 1 December 1998, Stévart 535 ( BRLU) ; Príncipe, Pico Papagaio , 110 m, s. d., Stévart 702 ( BRLU) . DEMOCRATIC REPUBLIC OF THE CONGO. Gandajika , 17 December 1956, Liben 2125 ( BRLU) ; Haut-Zaire, 60 km au Nord de Bengamisa, îles Gotsubo sur le Lindi , 7 March 1973, Lisowski 16921 ( BRLU) . UGANDA. Entebbe , 3,900 m, 6 September 1905, Brown 241 (K) ; Fort portal, golf course, May 1995, Spurrier U 47 (K) ; Bwaan , 3,900 m, 1905, s. coll. 279 (K) . BURUNDI. Mbuye, s. d., Delepierre & Lebel 167 ( BR). Without data, cult. in Netherlands , Wageningen , 24 February 1989, Arends 918 ( WAG) .

Distribution:— According to Govaerts et al. (2016), Cyrtorchis arcuata subsp. whytei occurs in twelve countries ( Sierra Leone, Liberia, Ivory Coast, Ghana, Togo, Democratic Republic of the Congo, Rwanda, Burundi, Tanzania, Malawi, Mozambique), although we have not examined any material from Sierra Leone, Ivory Coast, Ghana, Togo, Rwanda, Tanzania, Zambia and Mozambique.We have, however, seen specimens clearly assignable to this species from three other countries, noticeably extending its distribution both in Central Africa ( São Tomé & Príncipe and Cameroon) and in East Africa ( Uganda). Cyrtorchis arcuata subsp. whytei is thus widely distributed in Sub-Saharan Africa.

Habitat and ecology:— Epiphyte in forest galleries, swampy area and sclerophyllous scrub on lava ( Geerinck 1992) with the altitude range between 100 and 1,189 m elevation. Flowering peaks in May and June.

Notes:— This taxon differs from the type subspecies by its larger flower and its long sigmoid spur approaching that of C. chailluana ( Summerhayes 1960) .

Figures

FIGURE 3. Illustrative pictures of some central African taxa of the genus Cyrtorchis. A. C. arcuata. B. C. arcuata subsp. whytei. C. C. aschersonii. D. C. brownii. E. C. chailluana. F. C. hamata. G. C. henriquesiana. H. C. injoloensis. I. C. letouzeyi. J. C. monteiroae. K. C. ringens. L. C. submontana. Photographs ‘A–G’ & ‘I–L’ by Droissart Vincent and ‘H’ by Lourens Grobler.