Taxonomic revision of Sabicea subgenus Anisophyllae (Ixoroideae, Rubiaceae) from Tropical Africa, with four new species
Author
Zemagho, Lise A.
Plant Systematic and Ecology Laboratory, Higher Teachers´ Training College, University of Yaoundé I, P. O. Box 047, Yaoundé, Cameroon; Email: bonaventuresonke @ ens. cm & Department of Plant Systematics, University of Bayreuth, 95440 Bayreuth, Germany; Email: sigrid. liede @ uni-bayreuth. de
bonaventuresonke@ens.cm
Author
Liede-Schumann, Sigrid
Department of Plant Systematics, University of Bayreuth, 95440 Bayreuth, Germany; Email: sigrid. liede @ uni-bayreuth. de
sigrid.liede@uni-bayreuth.de
Author
Lachenaud, Olivier
Botanic Garden Meise, Belgium, Domein van Bouchout, BE- 1860 Meise, Belgium; Email: olivier. lachenaud @ botanicgardenmeise. be, steven. dessein @ plantentuinmeise. be & Plant Systematic and Ecology Laboratory, Higher Teachers´ Training College, University of Yaoundé I, P. O. Box 047, Yaoundé, Cameroon; Email: bonaventuresonke @ ens. cm & Herbarium et Bibliothèque de Botanique africaine, CP 265, Université Libre de Bruxelles, Av. F. Roosevelt 50, B- 1050, Brussels, Belgium.
olivier.lachenaud@botanicgardenmeise.be
Author
Dessein, Steven
Botanic Garden Meise, Belgium, Domein van Bouchout, BE- 1860 Meise, Belgium; Email: olivier. lachenaud @ botanicgardenmeise. be, steven. dessein @ plantentuinmeise. be
olivier.lachenaud@botanicgardenmeise.be
Author
Sonke, Bonaventure
Plant Systematic and Ecology Laboratory, Higher Teachers´ Training College, University of Yaoundé I, P. O. Box 047, Yaoundé, Cameroon; Email: bonaventuresonke @ ens. cm & Plant Systematic and Ecology Laboratory, Higher Teachers´ Training College, University of Yaoundé I, P. O. Box 047, Yaoundé, Cameroon; Email: bonaventuresonke @ ens. cm & Herbarium et Bibliothèque de Botanique africaine, CP 265, Université Libre de Bruxelles, Av. F. Roosevelt 50, B- 1050, Brussels, Belgium. & Plant Systematic and Ecology Laboratory, Higher Teachers´ Training College, University of Yaoundé I, P. O. Box 047, Yaoundé, Cameroon; Email: bonaventuresonke @ ens. cm & Missouri Botanical Garden, Africa & Madagascar Department, P. O. Box 299, 63166 - 0299, Saint Louis, Missouri, USA * Author for correspondence: lisezemagho @ ens. cm
bonaventuresonke@ens.cm
text
Phytotaxa
2017
2017-02-01
293
1
448
450
http://dx.doi.org/10.11646/phytotaxa.293.1.1
journal article
10.11646/phytotaxa.293.1.1
1179-3163
13695343
12.
Sabicea parmentierae
Zemagho, O. Lachenaud & Sonké
,
sp. nov.
(
Fig. 27
)
Type
:—
CAMEROON
.
Bidjap
,
32 km
E Nyabesan
,
7 March 1963
,
J. Raynal
&
A. Raynal
10282
(
holotype
P!;
isotype
YA
!)
.
Sabicea parmentierae
resembles
S. medusula
,
S. sthenula
and
S. mildbraedii
in general habit. It is best separated from these by the characteristic calyx lobes, with a narrow erect base bearing dense stiff hairs inside, and an enlarged apex bending outwards and much less pubescent; whereas, in the other species the calyx lobes are linear to triangular, with hairs evenly distributed on the inside. It also differs from
S. mildbraedii
in the calyx lobes
3.5–4.5 mm
long (vs.
1–3.5 mm
long) and the corolla with a red to pink tube
6.7–7 mm
long and white lobes (vs. entirely white, with tube
3.5–4.5 mm
long); and differs from
S. medusula
and
S. sthenula
in the flower buds with a strongly enlarged apex (vs. nearly cylindrical), the short-styled flowers with exserted stamens (vs. included), and the stipules with linear lobes (vs. entire or with relatively broad triangular lobes); and from all the above cited species in the corolla lobes
3–5 mm
long (vs.
1.5–3 mm
long), and the bracts entirely villose inside (vs. glabrous except at base).
Small, creeping rhizomatous herb
10–20 cm
tall; stems
1–2 mm
thick, main stems creeping, lateral flowering stems ascending and arcuate; persistently villose, with stiff patent purplish hairs ca.
3 mm
long, and sparsely white-felted when young. Leaves opposite, strongly unequal, one of them much smaller; smaller leaves with petioles
0.1–0.3 cm
long and blades 0.4–0.8 x
0.2–0.4 cm
; normal-sized leaves with petioles
0.5–3.8 cm
long, with same indumentum as the stems; blades elliptic to slightly obovate, 3.4–15.3 x
1.5–6.4 cm
, strongly asymmetrical at base with proximal side rounded to subcordate and distal side acute to subcordate inserted
2–7 mm
higher, gradually acuminate at apex, papery, strongly discolorous; upper side green, sparsely to densely villose with stiff hairs ca.
1 mm
long, and shorter uncinate hairs also present on the veins; lower side white or pinkish-buff, densely felted with woolly hairs, and villose on the veins (sometimes sparsely so on the lamina as well) with stiff hairs
1–1.5 mm
long; secondary veins 7–12 on each side of midrib. Stipules opposite, interpetiolar, connate at base with the reduced leaf and very shortly with the petiole of the normal leaf, erect to patent, 4–16 x
1.5–4 mm
, deeply divided (for ½ to ¾ of their length) into 3–7 linear segments
2–9 mm
long, sparsely villose outside with stiff hairs
1–1.5 mm
long (sometimes restricted to the margin) and sparse woolly hairs sometimes present as well, glabrous inside except the base with stiff hairs ca.
3 mm
long. Inflorescences axillary on leafy portion of stems, one per node, sessile, densely glomerulate, many-flowered,
0.9–1.8 cm
in diameter. Bracts and bracteoles ± hidden between the flowers, not enclosing them; bracts elliptic, ca. 4 x
1.5 mm
, entire or shortly dentate, acute at apex,villose on both sides, with stiff hairs ca.
1 mm
long; bracteoles narrowly elliptic to linear, 2–7 x
0.2–1.5 mm
, with same indumentum as the bracts. Flower buds with apex broader than long, much wider than the tube. Flowers 5-merous, sessile. Hypanthium densely hirsute. Calyx white outside, green with purple hairs inside; tube ca.
1.5 mm
long, villose with long stiff hairs outside, glabrous inside; lobes spathulate, sometimes narrowly so, 3.5–4.5 x (0.5–)
1–1.5 mm
, the apex acute or obtuse and conspicuously bending outwards, outside densely white-felted and sparsely villose with stiff hairs
0.7–2 mm
long, inside with long stiff hairs very dense on the narrow basal part and sparse or absent on the enlarged upper part. Corolla with red to pinkish tube and white lobes; tube 6.5–7 x
1–1.5 mm
, narrowly infundibuliform, ± widening near the apex; lobes triangular, 3–5 x
1.5–4 mm
; corolla tube glabrous outside, lobes densely villose outside, with stiff hairs
0.7–2 mm
long intermingled with short woolly hairs; mouth and base of lobes inside densely bearded with white moniliform hairs
1.5–2 mm
long; tube inside either villose at distal
2 mm
down to the base of anthers inside in long-styled flowers, or villose at distal
1 mm
and with 5 patches of short hairs ca.
2.5 mm
below the mouth (short-styled flowers). Stamens included, subsessile, attached ca.
2 mm
below mouth in long-styled flowers, exserted and +/- hidden between the hairs of the corolla mouth, with filaments ca.
1.5 mm
long inserted
2.5 mm
below mouth in short-styled flowers; anthers 1.5–2 x
0.4 mm
long. Disk cylindrical, ca.
0.3 mm
long, glabrous. Style glabrous,
8.5 mm
long, exserted, ± hidden between the long hairs of the corolla-mouth in long-styled flowers,
6 mm
long, included in short-styled flowers; stigmatic lobes ca.
1.5 mm
long, broadly elliptic and +/- flat. Fruits green to white (mature?), ellipsoid, 5–6 x
4.5–5 mm
when dry, densely villose with long hairs ca.
2 mm
long, subsessile. Seeds brown, polygonal, ca. 0.4 x
0.3 mm
, the surface with dense parallel striations.
54
•
Phytotaxa
293 (1) © 2017 Magnolia Press
ZEMAGHO
ET
AL.
TAXONOMIC REVISION OF
SABICEA
SUBGENUS
ANISOPHYLLAE
FIGURE 27.
Sabicea parmentierae
.
A, flowering stem; B, node with inflorescence, stipules and reduced leaf; C, portion of midrib and lateral nerve below with detail of indumentum; D, detail of a calyx lobe, outside; E, detail of a calyx lobe, inside; F, flower bud; G, long-styled flower; H, section of long-styled flower (calyx and ovary removed); I, section of short-styled flower; J, detail of a hair from the corolla mouth; K, detail of a hair from the outside of a corolla lobe; L, fruit. From
N.Hallé & Villiers 5048
(A, F–G),
Letouzey 10177
(B–C, J–K),
Lejoly 94/216
(D–E, L),
J. & A. Raynal 10282
(H–I). Drawing by Antonio Fernandez.
Phytotaxa
293 (1) © 2017 Magnolia Press •
55
Etymology:—
The species is named after Dr Ingrid Parmentier, formerly of the University of
Brussels
, specialist of the inselberg flora and one of its collectors.
Distribution:
—Lower
Guinea
Domain.
S. parmentierae
occurs in the extreme south of
Cameroon
,
Equatorial Guinea
, and northern
Gabon
(
Fig. 26
).
Habitat and ecology:
—Half-shaded places in forest, usually along streams, in low thickets on inselbergs, or along forest tracks; at
490–1110 m
altitude.
Phenology:
—Flowering in February–May and August–November; fruiting in January, March, May and October.
Discussion:
—
Sabicea parmentierae
resembles
S. medusula
,
S. sthenula
, and
S. mildbraedii
in general habit; the morphological differences are discussed in the diagnosis and are presented in
Table 5
. The species range is allopatric with respect to that of
S. mildbraedii
, although it partly overlaps with those of
S. medusula
and
S. sthenula
.
One of the first collections of
S. parmentierae
,
N. Hallé & Villiers
5048
from
Gabon
, was referred to
S. medusula
by
Hallé (1971)
. So far, we have not seen any specimen of
S. medusula
from
Gabon
, although the species is expected to occur there.
Although this species is well characterised, some collections showing intermediate characters with
S. medusula
and
S. batesii
have been noted; they are discussed under these two species.
Conservation status:—IUCN Red List Category: Near-Threatened [NT].
The extent of occurrence is estimated as
35,305.138 km
2
and the area of occupancy as
56 km
2
; the latter value falls within the limit for Endangered under criterion B2. The species is known from 14 subpopulations representing 13 locations (sensu
IUCN 2012
), which is above the limit for Vulnerable under the condition B2a. It occurs in two protected areas, Monte Alén National Park and the Monumento Natural de Piedra Bere, both in
Equatorial Guinea
. In view of its small range, and preference for inselbergs which are a vulnerable habitat, the species can be classified as near-threatened.
Additional specimens examined
(
Paratypes
):—
CAMEROON
.
South Province
:
Rocher d’Akoakas
(±
35 km
SE d’Ebolowa
),
6 May 2009
,
O.
Lachenaud
, B.
Lemaire
, M.
Simo
& B.
Sonké
600
(
BR
)
;
Colline Nkondo
près
Enyantoum
,
20 km
SW d’Ambam
,
19 March 1970
,
R. Letouzey
10177
(
BR
, P,
WAG
);
Akoakas
,
27 km
SE
Ebolowa
,
15 February 1963
,
J. Raynal
&
A. Raynal
9732
(P)
.
EQUATORIAL GUINEA
.
Bata – Mongo
(
Alosa
): estrada kms 77–78,
27 April 1995
,
M.F. de
Carvalho
5518
(
WAG
)
;
Parc National de Monte Alén
, transect
de Monte Chocolate
,
10 October 1994
,
J.
Lejoly
94/216
(
BRLU
)
;
Région d’Anisok
au dessus du village
Nzuamayong
,
Inselberg Akuom
,
11 September 1997
,
S.
Lisowski
M-678
(
BRLU
)
;
Région d’Anisok
au dessus du village
Nzuamayong
,
11 September 1997
,
S.
Lisowski
M-705
(
BRLU
)
;
Région d’Anisok
, environs
de Temelon
, près du village
Ayene
,
10 September 1997
,
S.
Lisowski
M-761
(
BRLU
)
;
Montagne
près
de Bikurga
,
23 September 1997
,
S.
Lisowski
M-1389, M-1465, M-1467
&
M-1472
(all
BRLU
)
;
Entre Nsuameyong
et inselberg
Akuom
,
16 January 1998
,
C.
Obama
& J.
Lejoly
447
(
BRLU
)
;
Parc National de Monte Alén
, dalle rocheuse
d’Engong
,
5 km
à l’ouest du village
d’Engong
,
2 July 1999
,
I.
Parmentier
& P.
Nguema
107
(
BRLU
)
;
Parc National de Monte Alén
, dalle rocheuse
de Monte Alén
,
15 May 2002
,
I.
Parmentier
& P
.
Esono
3082
(
BRLU
)
;
inselberg
de Bicurga
,
24 May 2002
,
I
Parmentier
& P.
Esono
3148
(
BRLU
)
;
Monte Alén
,
9 August 2001
,
B. Sonké
, P.
Esono
& S.
Ndong
2482
(
BR
,
BRLU
)
.
GABON
.
Akoga
,
8 February 1968
,
N. Hallé
&
J.F. Villiers
5048
(P);
Mintome
,
31 March 2003
,
R. Mboma
,
J. Lejoly
, A.
Boupoya
& B.
Sonké
98
(
WAG
)
;
Rougier Logging Concession
,
Haut Abanga
, east of
Ndjolé
,
18 February 2012
,
T.
Stévart
,
V. Droissart
,
A. Boupoya
,
E. Akouangou
, C.
Nyangala
& J.- N.
Boussiengui
4309
(
LBV
)
;
besides access road to hydroelectric facility at
Tchimbélé
,
17 November 2002
,
J.S.
Strijk
364
(
WAG
)
.