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
35.
Xylopia mildbraedii Diels, Bot. Jahrb. Syst. 53: 444. 1915.
Fig. 42C-D
Xylopia lastoursvillii
Pellegrin,
Mem
. Soc. Bot. France 1949: 71. 1950. Type. GABON.
Ogooue-Lolo
Province,
region
de Lastoursville, Koula motou, 13 Apr 1931,
G. Le Testu 8742
(lectotype, here designated: P! [00169128]; isolectotypes: BM! [000511051], BR! [0000008825308], LISC! [000404], OWU! P! [00169129, 00169130], WAG! [0247282, 0247283]).
Type
.
CAMEROON
.
South Region
,
Bezirk Kribi
, im
Vorland
mit eizeln
Huegeln
, bei
Beson
,
45 km
oestlich
Gross-Batanga
, bei
100-400 m
,
22 Jul 1911
,
J. Mildbraed
6055
(
holotype
: B! [100153148]; isotypes: HBG! [502477, 502478].
Description.
Tree
up to 9 m tall, rarely a shrub 3-4 m, d.b.h. up to 9 cm, trunk crooked, with diverging branches; bark smooth.
Twigs
brown, appressed-pubescent, the hairs 0.1-0.5 mm long, eventually gray-brown to orange-brown, glabrate; no nodes seen with two axillary branches.
Leaf
with larger blades 9.5-17.5 cm long, 3.2-5.6 cm wide, chartaceous, often discolorous but sometimes concolorous, elliptic to oblong, occasionally oblanceolate or lanceolate, apex acuminate, the acumen 8-19 mm long, base broadly cuneate, less commonly cuneate or rounded, glabrous except for the pubescent midrib adaxially, thinly and finely sericeous to glabrate abaxially, midrib impressed adaxially, raised abaxially, secondary veins indistinctly brochidodromous and slightly arcuate, 12-20 per side, diverging at 45-70° from the midrib, these and higher-order veins indistinct to slightly raised adaxially and slightly raised abaxially, rarely forming a raised reticulum on both surfaces; petiole 2-5 mm long, canaliculate, sparsely pubescent.
Inflorescences
axillary, 1-flowered, rarely 2-flowered from a second axillary pedicel superposed above the first, pubescent; peduncles absent; pedicels 3.7-6.4 (-8.5) mm long, 1.0-1.6 mm thick; bracts 3-4, evenly spaced along the pedicel, caducous or occasionally with uppermost persistent, 1.9-3.5 mm long, broadly triangular to semicircular, apex obtuse, acute, or apiculate; buds linear, sometime falcate, apex obtuse.
Sepals
slightly spreading at anthesis, 1/3-connate, 4.0-6.5 mm long, 3.6-5 mm wide, coriaceous, broadly triangular, apex acute, pubescent abaxially.
Petals
cream-colored
in vivo
; outer petals somewhat spreading at anthesis, 45-79 mm long, 3.6-5.5 mm wide at base, 2.2-4.1 mm wide at midpoint, fleshy, linear-ligulate, apex obtuse, with a longitudinal groove down the midline and puberulent adaxially, with a weak longitudinal ridge and sericeous, the hairs densest at the base, abaxially; inner petals more or less erect at anthesis, 35-61 mm long, 4.9-5.4 mm wide at base, 1.9-3.3 mm wide at midpoint, fleshy, linear, apex acute, base with undifferentiated margin, puberulent on both surfaces with a sericeous tuft just above the basal concavity adaxially, the hairs somewhat connivent.
Stamens
ca. 100; fertile stamens 1.4-1.9 mm long, narrowly oblong to clavate, apex of connective 0.3-0.5 mm long, capitate, overhanging anther thecae, papillate, anthers 11-12-locellate, filament 0.4-0.6 mm long; outer staminodes ca. 1.6 mm long, clavate, apex rounded to truncate; inner staminodes apparently absent; staminal cone ca. 2 mm in diameter, ca. 0.6 mm high, rudimentary, concealing only the very bases
of
the ovaries.
Carpels
10-11; ovaries 1.2-1.5 mm long, oblong, densely pubescent, stigmas connivent, 4.5-6 mm long, linear, bearing a tuft of hairs at apex and pilose on the sides.
Torus
flat, 2.7-3.3 mm in diameter.
Fruit
of up to 14 sparsely pubescent to glabrate monocarps borne on a pedicel 5-7 mm long, 5-7 mm thick, glabrate; torus 11-13 mm in diameter, 7-8 mm high, irregularly depressed-globose.
Monocarps
with pale green or yellowish green exterior and red to pink-red endocarp
in vivo
, 4.2-6.5 cm long, 1.3-1.5 cm wide, ca. 1.1 cm thick, oblong and sometimes falciform, weakly torulose, apex with a curved beak 1 mm long, base contracted into a stipe 9-15 mm long, 3-5 mm thick, flattened and grooved longitudinally, obliquely wrinkled, verrucose; pericarp ca. 0.5 mm thick.
Seeds
5-9 per monocarp, in a single row, lying oblique to long axis, 12.5-14 mm long, 6.5-8.5 mm wide, 5-7 mm thick, irregularly ellipsoid to oblong, wedge-shaped to oblong in cross-section, obliquely truncate at micropylar end, rounded at chalazal end, dark brown, smooth, shiny, raphe/antiraphe not evident, micropylar scar 3.5-4 mm long, 1.5-3 mm wide, ovate to elliptic, sometimes with a slight
"beak"
protruding through the center; sarcotesta frosty greenish blue, greenish white, or gray
in vivo
, sometimes visible as a white crust on dried seeds; aril absent.
Phenology.
Specimens with flowers have been collected in January, March, April, June, July, and December, and with fruits from December to February and in September.
Distribution
(Fig.
46
). Occurs in southern Cameroon and Gabon, in primary and older secondary forest at elevations of 100-520 m.
Figure 46.
Distributions of
Xylopia talbotii
and
X. mildbraedii
. Bolder lines represent country borders, fainter lines lakes and major rivers.
Additional specimens examined.
CAMEROON
.
20 km
from
Kribi
,
Lolodorf
road,
3°00'N
,
10°03'E
, newly opened forest exploitation (SFIA logging road),
9 Jun 1969
(fl),
Bos
4772
(B, M, MO, WAG-3 sheets); without definite locality,
M. Elad
1253
(WAG);
foret
de Bakaka
,
3 km
E of
Ebone
, a village on km 11
Nkongsamba-Loum
road,
4°50'N
,
9°54'E
,
520 m
,
13 Sep 1971
(fr),
Leeuwenberg
8362
(BR, K, MO, WAG-2 sheets)
.
GABON
.
Nyanga
: ca.
50 km
SW of
Doussala
,
2°36'S
,
10°35'E
,
10 Jan 1987
(fl),
Reitsma
&
Reitsma
2816
(MO, NY, RSA, WAG)
.-
Ogooue-Ivindo
:
Mboundou
,
SE Makokou
,
27 Feb 1961
(fr),
Halle
1350
(P); eastern border of
Lope-Okanda
Reserve
, along roads south of SEG lumber camp, west of
Offoue
River
,
0°27'S
,
11°45'E
,
200 m
,
15 Jan 1993
(fr),
McPherson 16070
(MO).-
Ogooue-Lolo
: about
40 km
E of Lastoursville
, ca.
0°50'S
,
13°05'E
,
14 Dec 1993
(fl, fr),
Breteler
&
Breteler-Klein
12632
(WAG-2 sheets);
Lastoursville
,
27 Dec 1929
(fl),
Le Testu
7824
(BM, OWU, P).-
Ogooue-Maritime
: Rabi, ca.
1°55'S
,
9°50'E
,
26 Mar 1990
(fl),
Breteler
et al. 9526
(WAG)
.
Xylopia mildbraedii
is a seldom-collected species, restricted in distribution. It is readily distinguished from its congeners by the petals reaching
79 mm
in length, surpassing all other African
Xylopia
species. It most resembles
X. thomsonii
and
X. unguiculata
in its overall appearance, but differs in having the hairs on the young twigs short and tightly appressed, larger leaves with more numerous and slightly arcuate secondary veins, a pronounced tuft of hairs on the inside of the inner petal base, a rudimentary to absent staminal cone, and larger and thicker-walled monocarps containing larger seeds. With these differences established, it was possible to determine that "
Xylopia
species A" of
Le Thomas (1969)
is a fruiting collection of
X. mildbraedii
. The sterile
collections
Reitsma & Reitsma 2732
and
Sosef et al. 1466
, both from
Gabon
, may also represent this species.
We calculated an EOO of
129,258 km
2 and an AOO of
36 km
2 for
Xylopia mildbraedii
.
Onana and Cheek (2011)
gave it a conservation assessment of Endangered, B2ab(iii).
Examination of the type material suggests that Pellegrin based the description of
Xylopia lastoursvillii
primarily upon one Paris collection of
Le Testu 8742
, which bears detailed drawings of flower parts; this collection is chosen as
lectotype
of this name.