neglectum (Dichapetalaceae), a second new species from Gabon with 4 - 5 - locular ovaries, with an adapted key to the Central African species
Author
Breteler, F. J.
text
Adansonia
2006
3
28
2
4
5
journal article
http://doi.org/10.5281/zenodo.5187034
1639-4798
5187034
Dichapetalum neglectum
Breteler
,
sp. nov.
(
Figs 1
;
2
)
Dichapetalo
heudelotii (Planch. ex Oliv.) Baill. var. heudelotii
primo adspectu maxime simile, sed ab eo differt floribus pedicellos inarticulatos et ovaria 4-5-locularia habentibus ut in
Dichapetalo
rabiense Breteler
;
a posteriore floribus majoribus perspicue pedicellatis differt.
TYPUS
. —
Gabon
.
Oveng
,
0°42’N
,
11°23’E
,
4.XI.1983
, fl.,
Louis
,
Breteler
&
de Bruijn
370 (holo-,
WAG!; iso-, AAU, B, BR!, C, FHI, K, LBV, LG, LISC, MA, MO, P, PRE, SRGH).
PARATYPES
. —
Gabon
.
15 km
ESE of Pana
,
X.1970
, ster.,
Breteler
6985
(
BR
!,
LBV
,
MO
,
WAG
!). —
S
.
l. 1904-1905, fr.,
Issembe
763
(
LBV
,
WAG
!)
.
DESCRIPTION
Liana or lianescent shrub. Branches and branchlets villous, lenticellate, glabrescent with age. Stipules appressed, triangular, (1.5-)
2-4 mm
long, pubescent outside, glabrous inside, caducous. Leaves: petiole subterete, grooved above, (3-)4-7(-8) mm long, hairy as branchlet; lamina papery, obovate, 2-2.5(-3) times as long as wide, (8-)10-20(-21) × (3-)4-8(-9) cm, cunate to rounded and often asymmetric at base, rounded to acute to very shortly (≤
0.5 cm
) acuminate at apex, densely villous both sides when young, soon glabrescent, especially so above except for the impressed midrib and beneath with remnants on and along the prominent midrib and the 8-13(-15) pairs of main lateral nerves; glands beneath only, alongside the midrib, distinct, flat to (often) almost semiglobose,
0.5-0.8 mm
in diam. Inflorescence a 1-3-flowered sessile cyme, single or racemosely arranged on short leaf less shoots, pubescent; bracts and bracteoles subtriangular, ± appressed,
1-1.5 mm
long, pubescent outside, glabrous inside. Pedicel
2-4 mm
long, inarticulate, pubescent, the overhung apical part ± glabrous. Calyx concave at insertion of pedicel. Sepals erect to somewhat spreading, oblong-triangular, shortly united at base, 3-4 ×
1.5-2 mm
, pubescent outside sparsely so inside. Petals erect, as long as the sepals, free at base, obovate-oblanceolate in outline,
4 mm
long,
1-1.5 mm
split, glabrous, lobes concave. Stamens erect, as long as or slightly longer than the petals,
4-5 mm
long, glabrous. Staminodes subquadrate in outline, 0.5 ×
0.5 mm
, glabrous, slightly bilobed. Pistil 4-5-merous,
5-6 mm
long; ovary 4-5-loculate, ± velutinous; style glabrous, 4-5-lobed; lobes ≤
0.5 mm
long. Fruit (immature) depressed globose, tuberculate, tomentose.
HABITAT AND DISTRIBUTION
Rain forest
of
Gabon
, altitude up to
c.
700 m
.
DISCUSSION
Besides the superficial resemblance to
Dichapetalum heudelotii
var.
heudelotii
to which the
type
material was first referred, the new species has characters in common with
D. leucocarpum
Breteler (2003)
and
D. rabiense
Breteler (1993)
.
B
FIG. 1. —
Dichapetalum neglectum
Breteler
:
A
, flowering branch;
B
, detail of leaf base beneath;
C
, compound inflorescence of sessile, 1-3 flowered cymes;
D
, flower with bracteole at base of pedicel;
E
, base of calyx with impressed scar of pedicel;
F
, flower, one sepal, two petals and one stamen removed, showing staminodes (disc glands) and developing fruit with style;
G
, immature fruit. A-F,
A.M. Louis et al. 370
; G,
Issembe 763
. Drawing by H. de Vries. Scale bars: A, B, 1 cm; C-G, 3 mm.
The latter species also has 4-5-merous pistils and lacks the articulation in its pedicels too. However, its flowers differ significantly in other characters from those of
D. neglectum
, like the length of the pedicel and the size of the flower. In
D. rabiense
the flowers are ± sessile and
c.
3 mm
long, in
D. neglectum
the flowers are
4-5 mm
long and have
2-4 mm
long pedicels. The fruit of
D. neglectum
has the same tuberculate pericarp as in
D. leucocarpum
. However, the flowers of the latter have (2-)3-locular ovaries and its pedicels are articulate.