Uapaca thouarsii Baillon

Mcpherson, Gordon, 2011, A review of Madagascan Uapaca (Euphorbiaceae s. l.), Adansonia (3) 33 (2), pp. 221-231 : 230-231

8. Uapaca thouarsii Baillon

Étude générale du groupe des Euphorbiacées: 596 (1858).

TYPUS. — Madagascar. Prov. Toamasina, Sainte Marie, 1834, fr., Bernier 252 (lecto-, P [sheet P00298675 ], here designated) .

REPRESENTATIVE MATERIAL EXAMINED. — Madagascar. Prov. Antsiranana, Ambondrobe , 13°42’49”S, 050°05’13”E, 5 m, 1.III.2003, Rabenantoandro 1399 ( MO, P, TEF) . — Marojejy , 14°27’15”S, 049°47’05”E, 757 m, 3-4.IV.1995, Rasoavimbahoaka 614 ( MO, P, TAN) . — Mangerivola , 18°12’S, 048°53’E, 540 m, 10-15.IV.1999, Ratovoson 67 ( MO, P, TAN) . — Prov. Toamasina, Ambodivato , 15°19’13”S, 049°33’29”E, 150 m, 20.XI.2002, Schatz 4001 ( MO, P) . — Farakaraina , 15°25’S, 049°52’E, 20-25 m, 11.II.1955, Service forestier 12913 ( G, K, MO, P) . — Tampolo , 17°17’00”S, 049°23’30”E, 10 m, 5.III.1957, Service forestier 16624 ( K, MO, P) . — Prov. Fianarantsoa, Nosy Varika , 21°13’30”S, 048°21’00”E, 14.II.2004, Ludovic 594 ( MO, P, TEF) . — Prov. Toliara, Andohahela , 250-500 m, 17-20.X.1992, Malcomber 1672 ( MO, P) .

DESCRIPTION

Trees 5-30 m high; stilt roots usually present; leafbearing twigs 3-5(-10) mm in diameter, solid, glossy only at tip, matte below. Leaf blades obovate to subelliptic, 6.5-17(-26.5) cm long, 2.5-8(-16) cm wide, base cuneate, attenuate into extended pulvinus, apex obtuse, secondary veins 4-6(-7, but up to 11 if leaves over 20 cm long) on each side of the midrib, evident, tertiary venation very obscure to invisible, non-scalariform; petiole 1.2-4.5(-7) cm long. Staminate peduncles 15-25(-35) mm long, petaloid bracts c. 8 mm long, c. 7 mm wide; flowering heads 5-6 mm in diameter excluding exserted stamens; staminodes present; pistillode pubescent on distal surface. Pistillate peduncles 15-47 mm long, petaloid bracts c. 6-8 mm long, 4-5 mm wide; calyx in flower 5-6 mm in diameter, irregularly lobed or erose, densely pubescent, not coated in exudate; ovary densely pubescent; calyx in fruit 1-3 mm high, 5-9 mm in diameter, usually persistently pubescent but occasionally nearly glabrate, not glossy, entire or somewhat lobed; fruit 2.2-3.0(-3.3) cm long, rounded or broadly attenuate at base, pointed or rounded at the top, occasionally smooth but more usually roughened by lenticel-like eruptions, pubescent but to varying degrees glabrescent.

DISTRIBUTION

Eastern forests from near sea level up to 1600 m.

REMARKS

Distinguished by its relatively broad leaves with few and evident secondary veins, obscure and non-scalariform tertiary venation, and by its typically densely pubescent, coarsely lenticellate fruit. Specimens from near the southern end of the eastern forest tend to have smaller leaves and a less pubescent, smoother fruit, but intergrade with specimens from more northerly populations. Narrow-leaved forms can be distinguished from U. littoralis by the latter’s more numerous secondary veins.