Four new endemic genera of Rubiaceae (Pavetteae) from Madagascar represent multiple radiations into drylands
Author
Block, Petra De
Botanic Garden Meise, Nieuwelaan 38, 1860 Meise, Belgium
petra.deblock@plantentuinmeise.be
Author
Rakotonasolo, Franck
Kew Madagascar Conservation Centre, Lot II J 131 Ambodivoanjo, Ivandry, Antananarivo, Madagascar & Parc Botanique et Zoologique de Tsimbazaza, Antananarivo- 101, Madagascar
Author
Ntore, Salvator
Botanic Garden Meise, Nieuwelaan 38, 1860 Meise, Belgium
Author
Sylvain G. Razafimandimbison,
Swedish Museum of Natural History, Department of Botany, P. O. Box 50007, SE- 10405 Stockholm, Sweden
Author
Janssens, Steven
Botanic Garden Meise, Nieuwelaan 38, 1860 Meise, Belgium
text
PhytoKeys
2018
2018-05-21
99
1
66
http://dx.doi.org/10.3897/phytokeys.99.23713
journal article
http://dx.doi.org/10.3897/phytokeys.99.23713
1314-2003-99-1
70092509EA3CFFCEAB02FFFAFFF6FFB6
1254650
Pseudocoptosperma menabense Capuron ex De Block
sp. nov.
Figs 10
, 13 A-C, J
Diagnosis.
Differing from
Coptosperma mitochondrioides
Mouly & De Block by the triangular, keeled stipules with a robust awn (vs. stipules of the "bec du canard" type with rounded tip) and the smooth fruits (vs. fruits with ca. 10 longitudinal ribs).
Type
.
MADAGASCAR
.
Mahajanga Province
,
foret
Tsimembo
, dans la concession
Barthe
,
19 Dec 1953
(fl.), Martin 8252-SF (
holotype
: P!; isotypes: BR!, TEF!)
.
Shrub or small tree to
8 m
tall, dbh to
10 cm
; young shoots bisulcate, dark brown, densely covered with short erect hairs; older branches pale brown or fawn, glabrescent, in dried condition strongly contrasting with the blackish-brown stipules and dark brown petioles. Leaves 5-12
x
1-2.5 cm
, narrowly elliptic or narrowly obovate; blades coriaceous, drying glossy and brown or more rarely greenish above, somewhat paler and dull below, glabrous on both surfaces; base cuneate to attenuate; apex acuminate, acumen
5-12 mm
long; midrib raised and secondary and tertiary nerves somewhat raised on the lower leaf surface; midrib impressed on the upper leaf surface; 10-16 secondary nerves on each side of the midrib. Petioles
2-6 mm
long, glabrous. Stipules drying blackish-brown, rapidly becoming corky, caducous, triangular with the robust awn as long as or longer than the basal sheath, glabrous outside, glabrous but with 2-3 basal rows of colleters inside; sheaths
1-2.5 mm
long; awns
2-4 mm
long. Inflorescences consisting of numerous flowers, 1-3.5
x
2-7 cm
, sessile; inflorescence axes, pedicels, bracts and bracteoles densely covered with short erect hairs, green but drying dark brown; bracts with stipular parts reduced and foliar parts triangular and vaulted,
1-2 mm
long, densely covered with appressed hairs and with a basal row of colleters inside, margins ciliate; central first order bracts often with stipular parts reduced and foliar parts leaf-like, 0.5-4
x
(0.2-)
0.4-0.9 cm
, elliptic or narrowly elliptic, base attenuate or cuneate, petiole
1-2 mm
long; bracteoles at the base of the ovary, broadly triangular,
0.4-0.7 mm
long, tips rounded to obtuse, with appressed hairs mostly in the upper half and a single colleter at each side of the base inside; first order axes
0.5-2.5 cm
long. Flowers sessile or shortly pedicellate, pedicels
0-1 mm
long with central flowers mostly sessile. Calyx green, glabrous outside; tube ca.
0.25 mm
long, glabrous and without colleters inside; lobes ovate,
0.2-0.3 mm
long, bases not overlapping but closely joining, tips rounded to obtuse, rarely acute. Corolla tube
1.5-2.5 mm
long, ca.
0.4 mm
in diameter at the base, ca.
1 mm
in diameter at the throat, glabrous outside, throat and upper third to half moderately to densely covered with erect hairs inside; lobes oblong, 2-2.5
x
0.75-1 mm
, glabrous on both surfaces, tip blunt and emarginate. Stamens completely exserted at anthesis; filaments <
0.5 mm
long; anthers
1.3-1.5 mm
long. Ovary
0.5-1 mm
long, green, glabrous. Style and stigma white, exserted from the corolla tube for
2-5 mm
at anthesis; style densely covered with spreading, upwardly directed hairs in upper half; stigma with upper
1.5-2 mm
fusiform, longitudinal papillate lines running down for a further
1-1.5 mm
. Fruits spherical,
3-3.5 mm
in diameter (persistent calyx not included), glabrous, drying dark brown, somewhat glossy and wrinkled when ripe; seeds ca.
2.5 mm
in diameter, dark brown.
Habitat.
Dry deciduous forest, on sand (white sand and laterite); alt. 0-800 m.
Distribution.
Occurring in western Madagascar from 23° to 15° 30'S; recorded in the Atsimo-Andrefana, Menabe, Melaky and Sofia Regions. Fig.
14D
.
Phenology.
Flowering: December-January; Fruiting: January-March.
Vernacular names.
Kerehetika (Martin 8252-SF); masonjohany (dialect Sakalava; Rabarivola 19861-SF); taolakena (dialect Sakalava; Ravelosaona 6592-SF); vahona (Harmelin 10202-RN bis).
Vernacular uses.
Wood used by Sakalava against headaches (Razafimandimbison & Bremer 487).
Critical notes.
Pseudocoptosperma menabense
strongly resembles a
Coptosperma
species. Like
Coptosperma
, it has coriaceous, glabrous leaves and terminal, sessile, compact inflorescences with pentamerous white flowers with small-sized corolla tubes, bracteoles, ovaries, calyx tubes and calyx lobes. Furthermore, the fruits have a single ruminate seed. However,
P. menabense
is unique within the group of species currently brought together under the name
Coptosperma
by the combination of the keeled triangular stipules with well-developed awn and the placentation (3 ovules pendulous from a small placenta attached to the upper half of the septum). Some
Coptosperma
species also have three pendulous ovules but their stipules are of a different type, notably, the "bec du canard" type (
Capuron 1973
). In this case the stipular sheaths are flat with a rounded or obtuse apex, i.e. they are pressed against each other in such a way that their margins meet without overlapping (
De Block et al. 2001
: fig. 1), whereas the stipules in
P. menabense
are folded around each other (visible only in the youngest stipule pair). Species without the "bec du canard" stipule type usually have ovules (1 to 3) impressed in a large placenta. - Some specimens in the herbarium TEF bear the name
Enterospermum menabense
Capuron, but the species was hitherto not formally described.
Preliminary IUCN assessment.
Vulnerable: VU B1ab(i,ii,iii,iv) + 2ab(i,ii,iii,iv). The extent of occurrence (EOO) of
Pseudocoptosperma menabense
, estimated to be 86,558 km2, exceeds the limits for the Vulnerable status under sub-criterion B1 but its area of occupancy (AOO), estimated to be 117 km2, falls within the limits for the Endangered category under sub-criterion B2. The species occurs in five locations, two of which are in protected areas: Zombitse-Vohibasia National Park and Kirindy Mitea National Park. The species is known from 16 collections, half of which were collected after the year 2000. The major threat for this species is habitat loss by logging for charcoal and timber, burning for grazing and slash-and-burn agriculture both inside and outside the protected areas (
Nicoll and Langrand 1989
). Hence, based on the above information, the species is listed as Vulnerable.
Additional specimens examined.
MADAGASCAR
.
Mahajanga Province
:
Menabe
,
foret
de Tsimembo
,
E
d'Ambereny
,
Antsalova
,
29-31 Mar 1966
(fr.),
Capuron
24598-SF (BR, P, TEF);
Antsalova
,
Ambereny
,
11 Jan 1959
(fr.),
Harmelin
10202-RN bis (BR, P, TEF); region of
Port
Berge
, along RN
6, 242 m
,
18 Mar 2010
(fr.),
De Block
,
Groeninckx
&
Rakotonasolo
2354 (BR, G, K, MO, P, S, TAN);
foret
Tsimembo
, dans la concession
Barthe
, district
Antsalova
,
17 Mar 1961
(fr.), Rabarivola 19861-SF (P, TEF)
;
Toliara Province
:
foret
de Jarindrano
, rive gauche du haut
Fiherenana
, E de
Maromiandry
,
Sakaraha
,
29 Dec 1961
(fl.),
Capuron
20569-SF (BR, P, TEF);
foret
d'Andranomena
,
entre Andranomena et Marofandilia, Morondava
,
19 Jan 1962
(fl.),
Capuron
20895-SF (BR, P, TEF);
Morondava District
,
foret
de Kirindi
, CFPF
Morondava
(
foret
d'Andalandahalo
), jardin botanique 2, c.
45 km
NE of Morondava
,
10 m
,
20 Feb 2000
(fr.), Davis,
Rakotonasolo
&
Wilkin
2564 (BR, K, TAN);
Kirindi forest
, N part - Conoco 7, 16 m,
19 Jan 2007
(fr.),
De Block
, Rakotonasolo,
Groeninckx
&
Dessein
2187 (BR, MO, P, TAN);
Morondava
,
Kirindi Forest
, close to ecotourist camp,
73 m
,
20 Jan 2007
(fr.),
De Block
, Rakotonasolo,
Groeninckx
&
Dessein
2208 (BR, K, MO, P, TAN);
Zombitse-Vohibasia National Park
, Zombitse,
31 Jan 2007
(fr.),
De Block
, Rakotonasolo,
Groeninckx
&
Dessein
2257 (BR, K, MO, P, TAN); Lamboukily,
14 km
of base camp in Kirindi,
42 m
,
20 Jan 2007
(fr.), Groeninckx, Rakotonasolo,
Dessein
&
De Block
102 (BR, MO, P, TAN); Lamboukily,
14 km
of base camp in Kirindi,
42 m
,
20 Jan 2007
(fr.), Groeninckx, Rakotonasolo,
Dessein
&
De Block
108 (BR, MO, P, TAN); Menabe,
55 km
NE of Morondava
, route 8 at CPPF,
Kirindy forest
,
0.25 to 0.5 km
NE of principal concession road,
4.5 km
E of route 8, block CN4 and CN5, 35 m,
19-20 Mar 1992
(fr.), Noyes, Harder, Rakotobe,
Razafindrabeaza
&
Abraham
1039 (BR, K, MO, P);
foret
d'Andranofotsy
situe
5 km
N du village du
meme
nom, Belo,
Tsirihihina
,
4 Jan 1953
(fr.), Ravelosaona 6592-SF (BR, TEF); Atsimo-Andrefana,
Zombitse-Vohibasia National Park
, along
Ritik'ala
trail,
700 m
from the start at the carpark,
750-800 m
,
3 Dec. 2003
(fl.),
Razafimandimbison
&
Bremer
487 (UPS)
.