Kylicanthe cornuata Descourvières, Stévart & Droissart, 2018

Descourvières, Pascal, Farminhão, João N. M., Dubuisson, Vincent Droissart Jean-Yves, Simo-Droissart, Murielle & Stévart, Tariq, 2018, A new genus of angraecoid orchids (Orchidaceae: Angraecinae) with highly distinctive pollinaria morphology, including three new species from tropical West and Central Africa, Phytotaxa 373 (2), pp. 99-120 : 108-110

Kylicanthe cornuata Descourvières, Stévart & Droissart , sp.nov. ( Figs. 2G , 6 )

Type :— CAMEROON. Centre : Mbam-Minkom (NW of Yaoundé), near Nye-Meyong village, inselberg included in dense forest with submontane affinity, 1,165 m, 3°55’58.32”N 11°22’26.58”E, 5 July 2008, Yaoundé shadehouse series 1127 (holotype: BRLU!; isotype: YA!) .

Kylicanthe cornuata is similar to K. bueae but differs in its non-resupinate flowers, horn-shaped spur, lack of a lip callus and erose to fringed petal margins.

Epiphytic herbs. Roots numerous, basal on the stem, unbranched, greyish, 2–3 mm diameter. Stem with a few leaves in a fan, up to 30 mm long, up to 6 mm in diameter. Leaves less than 10, oblong, elliptic, tessellated, margins entire, apex unequally bilobed with or without a notch of 0.5–2.0 mm, lobes subacute, 35–105 × 12–26 mm. Inflorescences usually 1–3, semi-pendent, emerging at the base of the stem, 3–8-flowered, 40–95 mm long, floral internodes about 3– 5 mm, rachis terete; bracts amplexicaul, about 2 mm long. Flowers non-resupinate, yellowish to green, turning orange late in anthesis, 6–13 mm in diameter; dorsal sepal elliptic, apex obtuse to subacute, margins entire, 3– or 5–veined, 4.0–6.0 × 2.0– 3.5 mm; lateral sepals elliptic, slightly asymmetrical, slightly keeled dorsally, apex obtuse to subacute, margins entire, 3–5-veined, 4.0–5.5 × 2.0–3.0 mm; angle between dorsal and lateral sepals about 120°; petals elliptic to sublinear, apex obtuse, margins eroded to fringed, 4.0–6.0 × 1.8–2.8 mm; lip broadly ovate, entire, margins entire to slightly erose, lateral margins not or slightly deflexed, 5–9-veined, ecallose, apex subacute or with a notch, 3.0–5.0 × 3.5–5.0 mm; spur horn-shaped, mouth widely spreading, laterally flattened in its distal part, apex rounded, 5–11 mm long; ovary and pedicel 4.5–7.0 × 0.7–1.0 mm. Column 1–2 × 2–3 mm; anther cavity approximately perpendicular to the axis of the column; stigmatic cavity large and cup-shaped, margins large and winged, 3 veins generally visible; rostellum triangular and bifid, 1.0– 1.5 mm long; pollinia 2, spherical; stipes 2, not fused, spoon-shaped with inner and outer margins subequal, fringed, 1.0– 1.5 mm long, connected to a single calceiform viscidium.

Distribution: —Southwestern Cameroon, Rio Muni ( Equatorial Guinea) and Gabon, 100–1,165 m ( Fig. 3 ).

Habitat and ecology: —Epiphytic in rainforest, where it is found around inselbergs and sporadically in old secondary forest.

Phenology: —Flowering March–November.

Conservation status: —The IUCN Red List category is vulnerable [VU]. The extent of occurrence (EOO) of K. cornuata is estimated to be over 40,163 km 2 (exceeding the 20,000 km 2 upper limit for vulnerable category under the criterion B1), whereas its minimal area of occupancy (AOO) is estimated to be 48 km 2, which falls within the limits for Endangered category under the criterion B2. Kylicanthe cornuata is endemic to Atlantic Central Africa and has been collected in one protected area, the Campo-Ma’an National Park ( Cameroon). It is also known from six subpopulations occurring in several unprotected forests subjected to selective logging, timber harvesting for small-scale subsistence and agriculture. This species is known from 25 specimens representing ten subpopulations. These ten subpopulations represent a total of nine “locations” (sensu IUCN 2017), exceeding the upper limit for Endangered category, but falling within the limits for vulnerable category. We project that the ongoing loss of its habitat will induce a continuous decline in the number of subpopulations and mature individuals in the next ten years as well as an important decline of its EOO and AOO. Kylicanthe cornuata is therefore assigned a preliminary status of VU B2ab(i,ii,iii,iv,v).

Etymology: —The species epithet refers to its distinctive horn-shaped lip spur.

Notes: — Kylicanthe cornuata is the only species of its genus with non-resupinate flowers. A specimen, Stévart 1745 (BRLU!), of this new species was observed by P.J. Cribb who made a first drawing of it in 2003, now conserved in the Kew Orchid Herbarium. With its trumpet-shaped ecallose lip with a wide mouth entrance and erose petal margins, K. cornuata looks somewhat like a dwarf Eurychone . This is the species identified as ‘ Diaphananthe sp. nov. ’ (CAM376 & CAM2338) in the phylogenetic trees of Simo-Droissart et al. (2018).

Additional specimens examined: — CAMEROON. Centre: Mbam-Minkom (région de, au NO de Yaoundé), village de Nye-Meyong, sommet d’une colline à l’Ouest du village, 1,120 m, 3°55’14.41”N 11°22’1.74”E, 10 June 2006, Yaoundé shadehouse series 370 (BRLU, YA) ; ibid. loc., 1,160 m, 3°55’25.43”N 11°22’4.80”E, 16 July 2008, Yaoundé shadehouse series 1151 (BRLU) ; ibid. loc., 9 July 2010, Yaoundé shadehouse series 2217 (BRLU) ; ibid. loc., 22 June 2011, Yaoundé shadehouse series 2896 (BRLU) ; village de Nye-Meyong, sommet de la colline située au N-NE du village, 1,130 m, 3°55’50.88”N 11°22’26.87”E, 5 July 2007, Yaoundé shadehouse series 582 (BRLU, YA) ; ibid. loc., 1,165 m, 3°55’58.32”N 11°22’26.58”E, 14 August 2007, Yaoundé shadehouse series 643 (BRLU) ; ibid. loc., 1 July 2008, Yaoundé shadehouse series 1115 (BRLU) ; Mont Kala, sommet de la colline, 1,138 m, 3°49’59.16”N 11°20’34.31”E, 17 June 2011, Yaoundé shadehouse series 2875 (BRLU, YA) ; ibid. loc., 27 July 2012, Yaoundé shadehouse series 3708 (BRLU) ; Sud: Massif de Ngovayan, Bidjouka, campement à 1 h 30 de marche au N-NO du village, 730 m, 3° 8’22.08”N 10°27’51.77”E, 14 July 2007, Yaoundé shadehouse series 732 (BRLU) ; Massif de Ngovayang, Bibondi, 830 m, 3°19’26.78”N 10°38’53.90”E, 14 September 2012, Yaoundé shadehouse series 3790 (YA) ; Bidou III/ Nkolembonda (route Kribi-Ebolowa), campement au pied du Mt des Éléphants, sur le versant Est, 350 m, 2°48’1.38”N 10° 0’42.54”E, 10 October 2008, Yaoundé shadehouse series 1384 (BRLU) ; ibid. loc., 14 March 2009, Yaoundé shadehouse series 1475 (P) ; ibid. loc., 20 March 2009, Yaoundé shadehouse series 1502 (BRLU, P) ; ibid. loc., 7 October 2009, Yaoundé shadehouse series 1860 (BRLU, P, WAG). ibid. loc., 25 October 2010, Yaoundé shadehouse series 2498 (YA) ; Bidou III/ Nkolembonda (route Kribi-Ebolowa), campement au pied du Mt des Éléphants à moins d’un km de la route qui va de Bidou III à HEVECAM, à 50 m du sommet, 445 m, 2°47’58.08”N 10° 0’16.86”E, 16 October 2009, Yaoundé shadehouse series 1885 (BRLU) ; Bifa (piste sur la route Kribi-Ebolowa), à 5 km au SE de Zingui, 105 m, 2°39’59.15”N 10°16’54.95”E, 19 September 2008, Yaoundé shadehouse series 1316 (BRLU) ; ibid. loc., 1 October 2009, Yaoundé shadehouse series 1828 (P, WAG) ; ibid. loc., 100 m, 2°40’10.98”N 10°16’54.48”E, 24 September 2008, Yaoundé shadehouse series 1337 (BRLU) ; ibid. loc., 2 November 2009, Yaoundé shadehouse series 1920 (BRLU) ; ibid. loc., 21 October 2011, Yaoundé shadehouse series 3245 (YA) . EQUATORIAL GUINEA. Rio Muni, Centro Sur: Bicurga (inselberg de), 12 July 2001, Stévart 948 (BRLU) . GABON. Woleu-Ntem: Crystal Mountains , c. 10km along the road Tchimbélé- Kinguélé, 29 October 1984, van der Laan 824 (WAG) ; Tchimbélé, forêt aux environs du barrage, 460 m, N0°36’878’’E10°24’168”, 25 August 2001, Stévart 1096 (BRLU) ; Assep-Bengong, frange forestière, 620 à 690 m, N01°38.631’, E11°37.314’, 18 August 2002, Stévart 1745 (BRLU, K-drawing) .

Figures

FIGURE 2. Overview of Kylicanthe diversity. A. Kylicanthe arcuata, plants growing as twig epiphytes in Mt. Etindé (Cameroon) and detail of the flowers. B. Kylicanthe perezverae, seed capsules of a plant grown at the Nimba shadehouse (Guinea). C. Kylicanthe liae, habit and detail of a flower showing a prominent orange viscidium, in cultivation at Huye orchid garden of the University of Koblenz- Landau guest house (Rwanda). D. Kylicanthe bueae, habit of a plant grown at Yaoundé shadehouse (Cameroon) and detail of a flower. E. Kylicanthe quintasii, detail of inflorescence of a plant from São Tomé Island. F. Kylicanthe rohrii, detail of inflorescence of a plant from Tanzania. G. Kylicanthe cornuata, detail of flowers of a plant grown at Yaoundé shadehouse (Cameroon). Photographs by: A., D. and G. Vincent Droissart; B. Ehoarn Bidault; C. Eberhard Fischer; E. Tariq Stévart; F. W. Bachmann, facilitated by the World Orchid Iconography of the Swiss Orchid Foundation at the Herbarium Jany Renz (Botanical Institute, University of Basel, Switzerland).

FIGURE 3. Distribution of the seven species of Kylicanthe in tropical Africa.

FIGURE 6. Kylicanthe cornuata. A. Habit. B. Inflorescence. C. Flower in lateral view. D. Flower in frontal view. E. Dorsal sepal. F. Lateral sepal. G. Petals. H. Lip in dorsal view. I. Column in frontal view. J. Column in lateral view. K. Column in frontal view showing rostellum. L. Anther cap. M. Pollinaria with pollinia still attached in lateral view. N. Pollinaria without pollinia in dorsal view. Drawn by Hans de Vries after Yaoundé shadehouse series 1127.