Chaetocarpus gabonensis Breteler, 2002

Breteler, F. J., 2002, Novitates Gabonenses 46. A new Chaetocarpus (Euphorbiaceae) from Gabon, Adansonia (3) 24 (2), pp. 221-227 : 221-222

Chaetocarpus gabonensis Breteler , sp. nov.

Chaetocarpo africano Pax affinis sed stipulis majoribus basi latiore, sepalis interioribus staminibusque floris masculi plus numerosis, disco floris feminei profunde lobato et parietibus fructus crassioribus differt.

TYPUS. — F.J. & B.J.M. Breteler 15570, Gabon, Moyen-Ogooué, 77 km La Lopé - Ndjolé road, ± 0°03’S, 11°10’E, 8 Aug. 2000, fr. (holo-, WAG; iso-, A, B, BR, E, FI, G, K, LBV, MA, MO, NY, P, PRE, S, US) .

Shrub or tree up to at least 25 m tall and 30 cm d.b.h. Branches pubescent, appressedly so or not to ± velutinous, glabrescent. Stipules foliaceous, ± appressed, rather long persistent, narrowly ovate to subobovate-elliptic, usually slightly falcate, (6-) 8- 12(-15) × (2-)3.5(-6) mm, 1-2.5 mm wide at base, rounded to acute at apex, appressed-pubescent outside, inside sparsely so to almost glabrous. Leaves: petiole subterete, (2-)3-5(-7) mm long, pubescent, appressedly so or not, glabrescent; lamina subcoriaceous, elliptic to oblong-elliptic or ovate-elliptic, (2-)2.5-3 times as long as wide, (6-) 10-15(-20) × (2-)4-7(-8) cm, rounded to slightly cuneate at base, acuminate at apex, the acumen mostly acute, 0.5- 1.5(-2) cm long; midrib slightly prominent above, distinctly so beneath, the (6 -) 9-11(-13) pairs of main lateral nerves ± parallel, plane to very slightly raised above, prominent beneath; appressed-pubescent on both surfaces when young, more densely so beneath, rather soon glabrescent, more rapidly so above. Flowers axillary, fasciculate; basal bracts minute, concave, suborbicular, pubescent. Pedicel pubescent, up to 2 mm long and articulate in male flowers, up to 1.5 mm in female flowers, up to 3 mm long in fruit. Male flower: sepals 6-7 (see note), spreading, outer two opposite, cuculate, suborbicular, ±1.5 mm in diam.; inner 4 sepals slightly concave, ± elliptic, 2.5-3 × 1.5- 2 mm, sparsely pubescent outside and with ciliate margin, glabrous inside, a fifth, smaller, more petaloid and glabrous inner sepal may be present. Stamens (12-)13(-14); filaments slender, variously united into an up to 3 mm long, pubescent column; free part of filaments ± 2 mm long, pubescent; anthers c. 0.7 mm long; pistillode rudimentary, pubescent. Disc glands narrowly ellipsoid, c. 0.5 mm long, glabrous. Femelle flower: calyx more or less as in male flowers; ovary subglobose, 1-2 mm long, sessile; styles bifid, shortly united at base, ± 3 mm long; disc ± 0.7 mm long, deeply and narrowly lobed, glabrous. Fruit capsular, slightly depressedsubglobose, 8-9 mm in diam., tuberculate, the tubercles pyramidal, crowned by a needle-like hair of c. 1 mm long; valves woody, 2-2.5 mm thick. Seeds black, glossy, sublenticular, ± 4 × 2 mm. — Figs. 1-3.

HABITAT AND DISTRIBUTION. — Gallery forest, forest edge in forest-savannah mosaic in Central Gabon North of Ogooué River and West of Ngounié River.

PARATYPES. — GABON: Aubréville 65, région de Ndjolé, 1 Sep. 1945, fr. ( P); Breteler & Jongkind 10523, 5- 15 km NNW of Ndjolé, 16 Nov. 1991, ster. ( LBV, WAG); Breteler et al. 10995, 5- 30 km NW of Ndjolé, 22 Apr. 1992, ster. ( WAG); Breteler et al. 13026, 27 Sep. 1994, Ƌ fl.b. ( LBV, MO, P, WAG); Breteler 13485, 8 km N of Ndjolé, 15 Mar. 1996, ster. ( LBV, MO, P, WAG); Breteler 14329, 28 Apr. 1998, ster. ( K, LBV, MO, WAG) ; F. J. & B. J .M. Breteler 15571, 77 km La Lopé-Ndjolé, 8 Aug. 2000, Ƌ fl. ( BR, G, K, LBV, MO, P, WAG) ; N . Hallé 2070, Lac Ezanga, 29 May 1963, Ƌ fl.b. ( P); Louis et al. 832, Kongo Boumba-Ayem road, 11 Nov. 1983, fr. ( BR, K, LBV, MA, MO, P, PRE, WAG) .

The two African species of Chaetocarpus may be distinguished as follows:

Stipules (6-)8-12(-15) × (2-)3-5(-6) mm with 1-2.5 mm broad base, sparsely pubescent to ± glabrous inside; leaves (sub)coriaceous, (6-)10-15(-20) × (2-)4-7(-8) cm with (6-)9-11(-13) pairs of main lateral nerves; male flower with 4(-5) inner sepals and with (12-)13(-14) stamens; disc in female flower deeply and narrowly lobed; fruit depressed-subglobose, 8-9 mm in diam., wall 2-2.5 mm thick ............................................ C. gabonensis Stipules 3-9 × (0.3-)0.5-1.2(-3) mm, constricted to a ≥ 0.5 mm wide base, usually appressed-pubescent inside; leaves ± papyraceous, 5-10(-15) × (1.5-)2-4(-7) cm, with (5-)6 -8(-10) pairs of main lateral nerves; male flower with 2-3(-4) inner sepals and with 8-10(-12) stamens; disc in female flower with undulate margin; fruit ellipsoidobovoid, 7-10 × 6-7 mm, wall 1-1.5 mm thick .............................................................................. C. africanus

Figures

Fig. 1. — Chaetocarpus gabonensis Breteler: A, branchlet with stipules and flowerbuds; B,C, stipule, outside and inside respectively; D, Ƌ flower; E, young fruit; F, part of fruit; G, detail of fruit wall. — Chaetocarpus africanus Pax: H, branchlet with stipules and flowerbuds; I,J, stipule, outside and inside respectively; K, part of fruit; L, detail of fruit wall. (A-C, Breteler c.s. 13026; D, Breteler c.s. 15571; E, Breteler c.s. 15570; F-G. Louis et al. 832; H-J, Breteler c.s. 12447; K-L, Breteler 6235). Drawing by W. WESSEL-BRAND.

Fig. 2. — Chaetocarpus gabonensis Breteler: fruiting branch of the tree from wich the type specimen has been collected. Photograph by F.J. BRETELER.

Fig. 3. — Distribution of Chaetocarpus in Gabon.