Dichapetalum neglectum Breteler, 2006

Breteler, F. J., 2006, neglectum (Dichapetalaceae), a second new species from Gabon with 4 - 5 - locular ovaries, with an adapted key to the Central African species, Adansonia (3) 28 (2), pp. 4-5 : 300-302

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

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.

Figures

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.

FIG. 2. — Distribution of Dichapetalum neglectum Breteler.