Cyrtorchis ringens (Rchb.f.) Summerhayes (1958: 87)

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 : 181-182

13. Cyrtorchis ringens (Rchb.f.) Summerhayes (1958: 87) . ( Fig. 3D ) Basionym: Listrostachys ringens Reichenbach (1878b: 266) . Angraecum ringens (Rchb.f.) Brown (1882: 873) . Homocolleticon ringens (Rchb.f.) Szlachetko & Olszewski (2001: 730) . Type:— CAMEROON. Sine loc., Hildebrandt in Bouché s. n. (holotype W!)

Heterotypic synonyms: Angraecum buchholzianum Kränzlin (1886: 334) . Listrostachys buchholziana (Kraenzl.) Durand & Schinz (1895: 48) . Cyrtorchis buchholziana (Kraenzl.) Schlechter (1918: 129) . Type:— CAMEROON. Mungo, J.T. Buchholz 974 (holotype B†).

Angraecum bistortum Rolfe (1893: 75) . Listrostachys bistorta (Rolfe) Rolfe (1897: 155) . Cyrtorchis bistorta (Rolfe) Schlechter (1918: 129) . Type:— NIGERIA. Interior of colony of Lagos, A.Moloney s. n. (holotype K!).

Listrostachys hookeri Rolfe (1897: 154) . Cyrtorchis hookeri (Rolfe) Schlechter (1918: 131) . Type:— CAMEROON. Cameroon Mountains, 1,200 –1,500 m, G.Mann 2114 (holotype K!).

Listrostachys ignoti Kränzlin (1914: 395) . Type:— CAMEROON. Mount Cameroon, s. coll. 18 (holotype B†).

Cyrtorchis belloneorum Chiron (2001: 77) . Type:— CAMEROON. Rives du lac Awing, vers 1200 m d’altitude, April 1999, R.Bellone 1050 ex G.Chiron X1050 (holotype LY).

Additional specimens examined:— SIERRA LEONE. Semnehun , Kailahun district, 17 October 1981, Segerbäck 1509 (K) ; ibid., 7 September 1982, Segerbäck 1509a (K) ; Sine loc., 11 November 1924, Regius Keeper 4 (K) . LIBERIA. Kitoma , 28 October 1951, Harley 1834 (K) . IVORY COAST. 61 km N of Sassandra, W of Niapidou , 19 January 1959, Leeuwenberg 2497 (K) ; Forêt de Daniefla , October 1971, Perez-Vera 129 (K) ; Forêt de Buyo , 11 October 1975, Perez-Vera 787 (K) ; Mt Tonkoui , 3 October 1961, Aké Assi 6025 (K) ; forêt de Tiapleu, 7 October 1960, Aké Assi 5673 (K); forêt de Taï, 22 October 1961, Aké Assi 6032 (K). CAMEROON. Mindourou site d’exploitation de la Pallisco près de Lomié (AC 5), 770 m, 12 September 2001, Stévart & Pial 210 ( BRLU) ; ibid., 12 September 2001, Stévart & Pial 218 ( BRLU) ; ibid., 4 October 2001, Stévart & Pial 232 ( BRLU) ; ibid., 5 September 2003, Stévart & Pial 898 ( BRLU) ; ibid., 12 September 2007, Droissart et al. ( Ombrière de Yaoundé ) 716 ( BRLU) ; ibid., 27 August 2007, Droissart et al. ( Ombrière de Yaoundé ) 672 ( BRLU, YA) ; ibid., 3 September 2008, Simo et al. ( Ombrière de Yaoundé ) 1275 ( BRLU) ; ibid., 14 September 2010, Simo et al. ( Ombrière de Yaoundé ) 2356 ( BRLU) ; ibid., 15 September 2011, Simo et al. ( Ombrière de Yaoundé ) 3144 ( MBG) ; ibid., 27 August 2012, Droissart et al. ( Ombrière de Yaoundé ) 3769 ( BRLU) ; Environs du village de Mindourou II, UFA gérée par Alpicam, 648 m, 14 August 2014, Droissart et al. (Ombrière de Yaoundé) 5388 ( BRLU) ; Bipindi , village de Memel II au Nord de Bipindi , Transect dans les collines (entre 250 et 275), 250 m, 24 September 2008, Simo et al. (Ombrière de Yaoundé) 1341 ( BRLU) ; ibid., 14 October 2010, Simo et al. ( Ombrière de Yaoundé ) 2469 ( BRLU) ; ibid., 8 October 2011, Simo et al. ( Ombrière de Yaoundé ) 3185 ( YA) ; ibid., 1 October 2012, Droissart et al. ( Ombrière de Yaoundé ) 3884 ( P) ; Bipinde, 1913, Zenker 4693 (K); Bindem (route allant vers Messama , perpendiculaire à la route Kribi-Ebolowa), arbre coupé pour servir de pont au-dessus de la rivière, à 1 heure de marche au SO du village, 570 m, 21 September 2007, Droissart et al. (Ombrière de Yaoundé) 747 ( BRLU) ; ibid., 19 October 2010, Simo et al. ( Ombrière de Yaoundé ) 2484 ( YA) ; ibid., 2 October 2012, Droissart et al. ( Ombrière de Yaoundé ) 3894 ( P, WAG) ; Nguti , sanctuaire de Banyang Mbo, village de Bejange, à environ 500 m du village de Babubok, situé à l’extrême S. de la réserve, 245 m, 25 October 2010, Simo et al. (Ombrière de Yaoundé) 2501 ( BRLU) ; ibid., 510 m, 12 November 2011, Simo et al. ( Ombrière de Yaoundé ) 3287 ( YA) ; ibid., 19 October 2012, Droissart et al. ( Ombrière de Yaoundé ) 3934 ( BRLU) ; Au sud du campement 552 (jusqu’à 2 km au sud du campement), 220 m, 1 November 2012, Droissart et al. (Ombrière de Yaoundé) 4005 ( BRLU) ; ibid., exploitation forestière, village de Tayov, 250 m, 1 November 2004, Droissart et al. ( Ombrière de Yaoundé ) 173 ( BRLU) ; ibid., 15 October 2008, Simo et al. ( Ombrière de Yaoundé ) 1395 ( BRLU) ; Parc National de Korup , dans le plot1 «structure» à proximité du Chimpanzee Camp, 299 m, 29 November 2012, Droissart et al. (Ombrière de Yaoundé) 4083 ( BRLU, YA) ; ibid., 6 October 2014, Droissart et al. ( Ombrière de Yaoundé ) 5586 ( BRLU) ; ibid., 300 m, 9 October 2014, Droissart et al. ( Ombrière de Yaoundé ) 5629 ( BRLU) ; Buea , Etinde, 1,600 m, 24 October 1992, Mbatchou 419 (K) ; Akom II (route Kribi-Ebolowa ), campement à 3 h de marche au S. du village, aux alentours du campement, à 10 de part et d’autre de la rivière, 705 m, 19 September 2008, Simo et al. (Ombrière de Yaoundé) 1306 ( BRLU, YA) ; ibid., chemin le long d’une rivière, jusqu’au pied du sommet 2 (1005 m), 660 m, 30 August 2010, Simo et al. ( Ombrière de Yaoundé ) 2328 ( WAG) ; Réserve Edéa-Douala , Lac Tissongo, 7 m, 20 October 2009, Simo et al. (Ombrière de Yaoundé) 1891 ( BRLU, P) ; ibid., 15 September 2010, Simo et al. ( Ombrière de Yaoundé ) 2364 ( P) ; ibid., 29 October 2010, Simo et al. ( Ombrière de Yaoundé ) 2519 ( YA) ; Mt Cameroon , 1,524 m, s. d., Johnston s. n. (K) ; Sine loc., 21 October 2011, Simo et al. (Ombrière de Yaoundé) 3227 ( BRLU) ; Nyasoso , Mt Kupe, shrike Trail, 1,275 m, 7 July 1992, Wheatley 399 (K) ; Sine loc., s. d., Hildebrandt s. n. (K); Sine loc., s. d., Mann 2114 (K). EQUATORIAL GUINEA (BIOKO, RIO MUNI). Bioco, 1989, Carvalho 3508 (K); Cataratas , chemin de Musumu au Rio Uele, 300 m, 6 October 1999, Ndong Bokung & Stévart 88 ( BRLU) ; village de Moca , PNMA, 650 m, 8 August 2001, Ndong Bokung & Stévart 386 ( BRLU) ; Bong , 20 September 2002, Ndong Bokung & Stévart 509 ( BRLU) . GABON. Western flanc of Monts Doudou, 6 December 1984, Arends et al. 653 (K) ; Song , Monts de Cristal, 8 November 2001, Biteau & Stévart 71 ( BRLU) ; Andocka-Foula , 21 September 2001, Ngok Banak 185 ( BRLU) ; ibid., 12 October 2001, Stévart et al. 1144 ( BRLU) ; ibid., 25 October 2001, Stévart et al. 1147 ( BRLU) ; ibid., 22 November 2001, Stévart & Ngok Banak 1145 ( BRLU) ; ibid., 1 December 2002, Stévart 1670 ( BRLU) ; ibid., 1 December 2002, Stévart 1734 ( BRLU) ; Medouneu , Kinguélé, 7 December 2001, Stévart et al. 1700 ( BRLU) ; ibid., 27 October 2002, Stévart 1790 ( BRLU) . BURUNDI. Bugesera , 17 December 1953, Liben 1050 (K) . RWANDA. Nyungwe , 24 February 2002, Delepierre & Lebel 101 (K) .

Distribution:— According to Govaerts et al. (2016), Cyrtorchis ringens occurs in twenty countries ( Sénégal, Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Nigeria, Equatorial Guinea, São Tomé and Príncipe, Cameroon, Gabon, Democratic Republic of the Congo, Uganda, Rwanda, Burundi, Angola, Tanzania, Zambia, Malawi, Zimbabwe), although we have not examined any material from Senegal, Guinea, Ghana, São Tomé and Príncipe, Democratic Republic of the Congo, Uganda, Angola, Tanzania, Zambia, Malawi, Zimbabwe. Cyrtorchis ringens is thus widely distributed in Sub-Saharan Africa.

Habitat and ecology:— Widely distributed in tropical forests, between 7 and 1,600 m elevation. Flowering peaks in September and December.

Notes:— According to Govaerts et al. (2016), Cyrtorchis ringens encompass five heterotypic synonyms: C. bistorta , C. hookeri , C. buchholziana , Listrostachys ignoti and C. belloneorum . The holotypes of C. buchholziana and L. ignoti were detroyed during the fire of Berlin herbarium in 1943 ( Summerhayes 1960). Additionally, we were not able to examine the holotype of C. belloneorum , which is housed in the herbarium of Lyon (LY). Examination of the two type’s specimens (Moloney s. n. and Mann 2114, respectively), deposited at Kew herbarium, allows us to confirm the synonymy with C. ringens .

The holotype of Cyrtorchis ringens , conserved at W, is poor and represents by one inflorescence and two flowers. We therefore used main distinctive features given in the protologue of Cyrtorchis ringens (Reichenbach and Heinrich 1878) , coriaceous slender leaves with equally bilobed apex, up to 9 cm long, the dense inflorescence, the imbricated leaves and the small depressed bracts, to identify the specimens cited in this paper. However, due to great morphological variations observed in specimens associated to C. ringens , we think that additional morphometric and molecular studies are needed to accurately clarify the delimitation of this taxon.

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.