Kylicanthe liae, Descourvières, Pascal, Farminhão, João N. M., Dubuisson, Vincent Droissart Jean-Yves, Simo-Droissart, Murielle & Stévart, Tariq, 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 : 110-111

Kylicanthe liae (Eb. Fisch., Killmann, J.-P.Lebel & Delep.) Descourvières, comb. nov. ( Fig. 2C )

Basionym: Diaphananthe liae Fischer, Killmann, Lebel & Delepierre, Orchidee (Hamburg) 62: 442. 2011. Type:— RWANDA. Western: Nyungwe National Park, road from Pindura to Bweyeye at km 18, 1,800 m, 15 February 2011, Lebel & Delepierre s.n. (holotype: BR!).

Description: —Epiphytic herbs. Roots numerous, basal on the stem, unbranched, greyish, up to 4 mm in diameter. Stem with a few leaves in a fan, up to 50 mm. Leaves distichous, less than 10, falcate, linear to obovate, subcoriaceous margins entire, apex unequally bilobate, 60–80 × 12–15 mm. Inflorescences usually 1–3, semi–pendulous, emerging at the base of the stem, with up to 8 flowers, 10–160 mm long, floral internodes about 10–20 mm, rachis terete; bracts amplexicaul, up to 2.5 mm long. Flowers resupinate, emerald green becoming yellow in late anthesis, up to 8–10 mm in diameter; dorsal sepal elliptic, apex obtuse to subacute, margins entire, 3.5–4.0 × 2.3–2.5 mm; lateral sepals elliptic, apex obtuse to subacute, margins entire, 3.8–4.8 × 1.8–2.8 mm; angle between dorsal and lateral sepals about 90°; petals elliptic sublinear, apex obtuse to subacute, margins entire, 1–3-veined, 3.2–3.5 × 1.2–1.5 mm; lip cordate, entire, margins entire, lateral margins slightly deflexed, with a callus, apex subacute, about 4 × 3 mm; lip callus, a small tooth in the mouth of the spur; spur tubular, clearly sigmoid, circular in cross section, more or less pendent, mouth slightly spreading, proximal part of the spur approximately parallel to the ovary, apex rounded and only barely broadened, 20–24 mm long; ovary and pedicel about 8–9 × 1 mm. Column 2.2–3.0 × 1.6–2.0 mm; anther cavity approximately perpendicular to the axis of the column; stigmatic cavity cup-shaped, margins winged, 3 veins; rostellum triangular and bifid, about 1 mm long; pollinia 2, spherical; stipes 2, separate along their length, spatulate with slightly fringed margins, about 1.4 mm long, connected to a single calceiform viscidium.

Distribution: —This species is probably endemic to the Albertine Rift. Recorded in Rwanda (Nyungwe Forest) and southwestern Uganda (Kalinzu Forest), 1,500 –1,800 m ( Fig. 3 ).

Habitat and ecology: —Epiphytic in the canopy of montane forests.

Phenology: —Flowering February–April.

Conservation status: —The IUCN Red List category is Endangered [EN]. The extent of occurrence (EOO) of K. liae cannot be calculated since the species is known from two subpopulations, whereas its minimal area of occupancy (AOO) is estimated to be 8 km 2, which falls within the limits for Critically Endangered category under the criterion B2. Kylicanthe liae is endemic to Albertine Rift and has been collected only in two protected areas. This species is thus known from two specimens representing two subpopulations. These two subpopulations represent a total of two “locations” (sensu IUCN 2017), which falls within the limits for Endangered category. We suspect that the past loss of its habitat had induced a continuous decline in the number of subpopulations and mature individuals as well as an important decline of its EOO and AOO. Kylicanthe liae is therefore assigned a preliminary status of EN B2ab(i,ii,iii,iv,v).

Notes: —This species can be easily confused with K. quintasii , to which it is sympatric. However, K. liae has flowers distinctly green and not yellow or orange and a significantly longer sigmoid spur ( Fischer et al. 2011). The only known specimen of K. liae from Uganda (Meyer 129 in Stewart) (vide Cribb 1989) was misidentified as Diaphananthe bueae .

Additional specimens examined: — UGANDA. Western: Kalinzu Forest: 1,525 m, 12 April 1971, flowered 18 February 1975, Meyer 129 in Stewart (K).

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.