Hancea inhospita McPherson, 2012

McPHERSON, Gordon, 2012, A new Madagascan species of Hancea Seem. (Euphorbiaceae), Adansonia (3) 34 (1), pp. 71-75 : 72-74

Hancea inhospita McPherson , sp. nov.

( Fig. 1 )

Ab ceteris speciebus madagascariensibus cognitis foliis ovatis vel ellipticis domatiis nullis differt.Ab H. spinulosa laminis foliorum apice late acuminatis vel aliquando obtusis (nec anguste acuminatis), nervis in axillis domatiis non instructis, stipulis brevibus (1-2 mm contra 3-5 mm), floribus staminatis bracteis brevibus (1 mm contra 1.5-3 mm) et staminibus paucioribus (45-50 contra 80-90) distinguenda.

TYPUS. — Madagascar. Prov. Toamasina, Ambatovy, NE of Moramanga , low, dense forest on lateritic soils, 18°51’12”S, 48°18’48”E, 1100 m, 26.II.1998, fl., fr., McPherson 17461 (holo-, MO! [#5888427]; iso-, K, MO!, P, TAN) .

PARATYPI. — Madagascar. Prov. Toamasina, parc national de Zahamena, NW de la rivière Moango, 17°33’57”S, 48°53’58”E, 740 m, 24.X.2000, fl., fr., Randriamanarivo 17 ( MO, P, TAN) . — Ambatovy, forêt d’Analamay Sud , 18°48’18”S, 48°19’48”E, 1220 m, 18.XII.2004, fl., Andriamahefarivo 47 ( MO, P, TAN) ; idem, 18°48’25”S, 48°20’43”E, 1095 m, 9.X.2007, fl., fr., Bernard 602 ( MO, P, TAN) ; idem, 18°49’25”S, 48°20’04”E, 1068 m, 31.III.2005, fr., Rakotovao 1701 ( MO, TAN) ; idem, 18°49’58”S, 48°19’46”E, 1061 m, 11.III.2005, fr., Rakotovao 1614 ( MO, P, TAN) ; idem, 18°50’53”S, 48°18’29”E, 1124 m, 12.X.2005, fl., Razanatsoa 67 ( MO, P, TAN) ; idem, 18°51’07”S, 48°17’49”E, 1109 m, 16.II.2005, fl., fr., Rakotovao 1183 ( MO, P, TAN) ; idem, 18°51’22”S, 48°18’34”E, 1141 m, 2.III.2005, fl., Rakotovao 1461 ( MO, TAN) ; idem, 18°51’24”S, 48°17’41”E, 1000 m, 6.III.1997, fl., Rakotomalaza 1258 ( MO, P, TEF) ; idem, 18°51’34”S, 48°18’25”E, 1050 m, 27.II.1997, fl., Rakotomalaza 1196 ( MO, P, TEF) . — Prov. Fianarantsoa, Farafangana , forêt de Manombo, 23°10’12”S, 47°42’50”E, 21 m, 24.III.2004, fl., Ludovic 672 ( MO, P, TAN) . — Prov.Tulear, Fort-Dauphin, forêt d’Ivohibe , 24°34’14”S, 047°12’04”E, 265 m, 28.XI.2005, fr., Razakamalala 2438 ( MO, P, TAN) ; idem, 24°33’52”S, 47°11’43”E, 386 m, XI.2005, fl., Razakamalala 2446 ( MO, P, TAN) .

DESCRIPTION

Small tree 2-8 m; diameter at breast height up to 12 cm; young twigs glabrous,often resinous near tips; stipules subulate, 1.5-2 mm long, caducous. Leaves opposite to subopposite and unequal, or alternate. Blades elliptic-oblong to occasionally ovate,the smaller 1.4-6.5 × 0.9-2.8 cm, the larger 2.3-16× 1.2-4.5 cm, somewhat coriaceous, obtuse to broadly cuneate at the base, typically rather broadly acuminate at the apex but sometimes merely acute or even obtuse (most often in smallest leaves); midrib raised on both surfaces, usually pubescent abaxially with erect hairs more than 0.5 mm long, but sometimes glabrate or glabrous;secondary veins8-12on each side of the midrib, domatia absent; both surfaces without glandular granules or embedded circular glands, glabrous except for the midrib abaxially.Shorter petioles 2-25 mm, the longer 4-43 mm, narrowly canaliculate, pulvinate at both ends, often pubescent abaxially like the midrib but sometimes glabrate or glabrous.

Plants monoecious or (apparently) dioecious. Staminate inflorescences racemiform, axillary, 2-5 cm long, resinous-scurfy, flowers solitary along the axis or in groups of 2-3, bracts up to 1 mm long, quickly caducous, pedicels 1-1.5 mm; buds 1.5-2 mm in diameter; sepals 3-4, 1.5-2.5 mm long; stamens 45-50 in number. Pistillate inflorescences axillary; peduncle 2-7 cm long, bearing a single terminal flower; pedicel c. 1 mm; calyx of five subulate sepals 1-3 mm long; styles not seen. Fruit c. 6 mm high, 9-10 mm in diameter, minutely papillate-granular and puberulent-glabrate, spinulose, each sixth of the capsule bearing one spinule up to 2 mm long.

DISTRIBUTION AND ECOLOGY

Hancea inhospita sp. nov. is endemic to the humid evergreen forests of eastern Madagascar on lateritic soils or sand at recorded elevations from 21 to 1220m ( Fig. 2 ).

REMARKS

The new species differs in leaf shape and apex from Hancea capuronii (Leandri) S.E.C.Sierra, Kulju & Welzen , which is the only Madagascan species having obovate to oblanceolate leaves with obtuse apices. From the four other Madagascan species known, H. inhospita is easily distinguished by its lack of leaf domatia. It most closely resembles H. spinulosa but differs in having leaves with shorter and broader tips, in lacking leaf domatia entirely, and in having shorter stipules (1-2 mm vs 3-5 mm), shorter staminate bracts (1 mm vs 2-3 mm) and fewer stamens per staminate flower (45-50 vs c. 100).

E TYMOLOGY

The specific epithet, meaning “not providing shelter”, was suggested by the fact that Hancea inhospita can be most readily separated from its congeners with similar leaves by its lack of domatia in the axils of the leaf veins.

KEY TO HANCEA SEEM. IN MADAGASCAR

1. Leaves obovate to oblanceolate, the apex obtuse ............................................................ .................................................... H. capuronii (Leandri) S.E.C.Sierra, Kulju & Welzen

— Leaves ovate or elliptic, the apex acuminate or acute, rarely obtuse ............................. 2

2. Twigs densely pubescent ............... H. acuminata (Baill.) S.E.C.Sierra, Kulju & Welzen

— Twigs glabrous or obscurely puberulent ...................................................................... 3

3. Domatia present in axils of leaf veins .......................................................................... 4

— Domatia absent ......................................................... H. inhospita McPherson , sp. nov.

4. Fruit less than 10 mm in diameter (excluding spinules); spinules up to 4 mm long, 6- c. 24 in number ............................. H. spinulosa (McPherson) S.E.C.Sierra, Kulju & Welzen

— Fruit more than 15 mm in diameter (excluding spines); spines 5-15 mm long, more than 25 in number ............................................................................................................. 5

5. Leaf apex long-acuminate; petiole not canaliculate; known only from Ampasindava Peninsula .............................................................................................................. H. sp. 1

— Leaf apex shortly and broadly acuminate; petiole canaliculate, at least distally; known only from the summit of Mt. Vohimarangitra ................................................. H. sp. 2

Figures

FIG. 1.— Hancea inhospita McPherson, sp. nov.: fruiting branchlets, McPherson 17461, holo-, MO.

FIG. 2.— Distribution of Hancea inhospita McPherson,sp.nov.(l) mapped on the bioclimatic zones of Madagascar (after Cornet 1974; see Schatz 2000).