A revision of Xylopia L. (Annonaceae): the species of Tropical Africa
Author
Johnson, David M.
Department of Botany-Microbiology, Ohio Wesleyan University, Delaware, OH, 43015, USA
Author
Murray, Nancy A.
Department of Botany-Microbiology, Ohio Wesleyan University, Delaware, OH, 43015, USA
namurray@owu.edu
text
PhytoKeys
2018
2018-04-24
97
1
252
http://dx.doi.org/10.3897/phytokeys.97.20975
journal article
http://dx.doi.org/10.3897/phytokeys.97.20975
1314-2003-97-1
BD026E15CD67FF99E01FF605FFF6FFEF
1239255
44
.
Xylopia unguiculata D. M. Johnson & N. A. Murray
sp. nov.
Fig. 33A-D, L-O
Diagnosis.
Species resembling
X. acutiflora
in the tree habit, mixture of long and short erect hairs on the twigs, short pedicels 2.8-4.8 mm long, and outer petals up to 2.5 mm wide at midpoint, but differing in the cuneate to broadly cuneate leaf base and the strongly torulose monocarps with seeds in a single row and a prominent beak at the apex.
Type
.
GABON
.
Nyanga Province
, ca.
50 km
SW of
Forestry Camp Doussala
,
2°36'S
,
10°35'E
,
20 Feb 1986
,
J. M. Reitsma
&
B. Reitsma
1923
(
holotype
: WAG! [0050003]; isotypes: MO! [3879083], NY!
RSA
!).
Description.
Tree
up to 17 m tall, rarely a shrub, d.b.h. up to 16 cm; bark smooth.
Twigs
brown, pilose-pubescent, with a mixture of dense hairs 0.1-0.2 mm long and sparser longer hairs 0.7-1.3 mm long, at length gray-brown to dark brown, glabrate, with the bark somewhat exfoliating; nodes rarely with two axillary branches.
Leaf
with larger blades 8.9-12 cm long, 3.0-4.5 cm wide, chartaceous, slightly discolorous, elliptic to somewhat oblanceolate, obovate, or oblong, apex acuminate, the acumen 4-13 mm long, base cuneate to broadly cuneate, glabrous except for the pubescent midrib adaxially, sparsely appressed-pubescent to glabrate abaxially; midrib slightly impressed adaxially, raised abaxially, secondary veins indistinctly brochidodromous, 8-14 per side, diverging at 45-75° from the midrib, these and higher-order veins plane to slightly raised adaxially, raised abaxially; petiole 2.5-6 mm long, canaliculate, sparsely pubescent.
Inflorescences
axillary or from the axils of fallen leaves, 1-flowered, densely pubescent; pedicels not pedunculate, 2.8-4.8 mm long, 1.4-1.5 mm thick; bracts 3-4, imbricate, persistent, 2.3-3.8 mm long, orbicular, apex rounded to emarginate; buds linear, apex obtuse.
Sepals
slightly spreading at anthesis, 1/4-1/3-connate, 2.8-3.9 mm long, 3.4-3.6 mm wide, coriaceous, broadly ovate, apex acute to obtuse, densely brown-tomentose abaxially.
Petals
white to pale yellow with a patch of purple on the adaxial base
in vivo
; outer petals slightly spreading at anthesis, 22-30 (-46) mm long, 3.4-4.5 mm wide at base, (1.4-) 2.2-2.5 mm wide at midpoint, coriaceous, linear, apex acute to obtuse, glabrous and somewhat verrucose on lower half but otherwise puberulent adaxially, sericeous abaxially; inner petals appearing bent outward at the base at anthesis, 15.5-25 (-29) mm long, 3.0-3.6 mm wide at base, 1.2-1.6 mm wide at midpoint, coriaceous, linear, apex acute, glabrous on proximal 1/3-1/2 but otherwise puberulent adaxially, puberulent except for the glabrous base abaxially.
Stamens
90-160; fertile stamens 1.2-1.9 mm long, clavate to narrowly oblong, apex of connective purple
in vivo
, 0.2-0.4 mm long, dome-shaped to shieldlike, overhanging the anther thecae, minutely papillate, anthers 9-13-locellate, filament 0.2-0.7 mm long; outer staminodes 1.2-1.9 mm long, clavate or oblong, apex obtuse to truncate; inner staminodes 0.8-0.9 mm long, clavate, apex truncate; staminal cone 1.9-2.1 diameter, 0.6-1.1 mm high, concealing the lower half of the ovaries, rim laciniate.
Carpels
10-15; ovaries ca. 1 mm long, oblong, densely pubescent, stigmas connivent except for the free apices, ca. 3 mm long, linear, glabrous except for tuft of hairs at apex.
Torus
flat, 1.8-2.5 mm in diameter.
Fruit
of up to 20 sparsely pubescent to glabrate monocarps borne on a pedicel 6.7-9 mm long, 3.3-6.5 mm thick, with sepals and bracts persistent, glabrate; torus of fruit ca. 8 mm in diameter, 5 mm high, depressed-globose.
Monocarps
with green exterior and red endocarp
in vivo
, 4.9-8.5 cm long, 0.8-0.9 cm wide, 0.7-0.8 cm thick, narrowly oblong, strongly torulose, almost moniliform, apex rostrate, the beak 2.5-6 mm long, strongly curved, base contracted into a flattened and grooved stipe 8-18 mm long, 1.9-2.1 mm thick, slightly wrinkled and verrucose; pericarp 0.1-0.3 mm thick.
Seeds
up to 8 per monocarp, in a single row, parallel or oblique to long axis, 11.9-12.4 mm long, 6.6-7.5 mm wide, 6.0-7.0 mm thick, oblong, more or less circular in cross-section, truncate at micropylar end, rounded at chalazal end, smooth or slightly bumpy, dull, raphe/antiraphe not evident, micropylar scar 3.3-4.6 mm long, 2.9-4.5 mm wide, broadly elliptic or roughly circular; sarcotesta unknown
in vivo
, sometimes forming a white crust on dried seeds; aril absent.
Phenology.
Specimens with flowers have been collected in February, March, May, July, and December, and with fruits from October to December.
Distribution
(Fig.
34
). Gabon, with one collection from the northern part of the country near the border with Cameroon and the remainder from southern Gabon, in primary rainforest or exploited high forest, at elevations of 250-650 m.
Additional specimens examined.
GABON
.
Nyanga
:
Tchibanga
,
5 Oct 1907
(fr),
Le Testu
1179
(BM, P);
forets
du Mayombe
,
Tchibanga
,
Dabilila
,
15 Nov 1908
(fr),
Le Testu
1446
(BM, P);
Mayombe
bayaka,
Dabilila
,
11 Dec 1908
(fl),
Le Testu
1514
(BM-2 sheets, MO, P);
region
Nyanga
,
Tchibanga
,
8 Dec 1914
(fr),
Le Testu
1903
(BM, P); chantier CEB, ca.
50 km
SW of Doussala
,
2°36'S
,
10°35'E
,
26 Aug 1985
(buds),
Reitsma
&
Reitsma
1401
(MO, NY, RSA)
;
about
30 km
NW of Doussala
, in the direction of
Bongo
,
400 m
,
16 Mar 1988
(fl),
de Wilde
&
Jongkind
9393
(MO, WAG).-
Ogooue-Maritime
: 32 road-km N of
Igotchi-Mouenda
,
Bakker
timber concession,
250 m
,
02°41'S
,
10°30'E
,
13 May 1977
(fl),
McPherson 16960
(MO),
McPherson 16960A
(MO).-Woleu-Ntem:
region
entre
Ogooue
et Cameroun, Mbabou
,
31 Jul 1933
(fl),
Le Testu
9208
(BM, K, P)
.
Xylopia unguiculata
bears monocarps with distinctive claw-like apices; the specific epithet alludes to this apex shape. The illustration of the fruit identified as
X. acutiflora
in
Le Thomas (1969)
shows the appearance of the apex well. The new species shares with
X. acutiflora
from West Africa a tree habit and a short pedicel covered by imbricate bracts.
Xylopia unguiculata
differs, however, in its cuneate to broadly cuneate, rather than broadly cuneate to rounded leaf base, broader outer petals, and a larger number of falciform, strongly torulose monocarps with the prominent claw-like beak and seeds in a single row. [Note: The illustrations in
Le Thomas (1969)
provided for
Xylopia acutiflora
show a mixture of two species, the flowers and floral parts being based on
Bates 1852
, identified here as
X. thomsonii
, and the fruits on
Le Testu 1179
, identified as
X. unguiculata
.]
Xylopia unguiculata
may prove to be more widely distributed, but as known at present it is endemic to the
Congo
Subregion within the Congolian Biogeographic Region of
Linder et al. (2012)
. It is of potential conservation concern, with an EOO of
15,417 km
2 and AOO of
20 km
2.