A new genus of angraecoid orchids (Orchidaceae: Angraecinae) with highly distinctive pollinaria morphology, including three new species from tropical West and Central Africa
Author
Descourvières, Pascal
Institut de Systématique, Évolution, Biodiversité ISYEB, Sorbonne Université, CNRS, MNHN, EPHE, 57 rue Cuvier, CP 48 F- 75005, Paris, France
Author
Farminhão, João N. M.
Herbarium et Bibliothèque de Botanique africaine, Université Libre de Bruxelles, campus de la Plaine, boulevard du Triomphe, CP 265, B- 1050, Brussels, Belgium
Author
Dubuisson, Vincent Droissart Jean-Yves
Author
Simo-Droissart, Murielle
Plant Systematics and Ecology Laboratory, Higher Teachers’ Training College, University of Yaoundé I, Yaoundé, Cameroon
Author
Stévart, Tariq
Herbarium et Bibliothèque de Botanique africaine, Université Libre de Bruxelles, campus de la Plaine, boulevard du Triomphe, CP 265, B- 1050, Brussels, Belgium & Missouri Botanical Garden, Africa & Madagascar Department, PO Box 299, St. Louis, Missouri 63166 - 0299, USA
text
Phytotaxa
2018
2018-10-24
373
2
99
120
http://dx.doi.org/10.11646/phytotaxa.373.2.1
journal article
10.11646/phytotaxa.373.2.1
1179-3163
13727438
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).
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
.
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)
.