Aralia hiepiana J. Wen & Lowry, 2002

Wen, Jun & Lowry Ii, Porter P., 2002, Aralia hiepiana J. Wen & Lowry, a new species of Araliaceae from Vietnam, Adansonia (3) 24 (2), pp. 213-216 : 214-216

Aralia hiepiana J. Wen & Lowry , sp. nov.

Arbuscula aculeata . Folia bipinnata ; foliola chartacea, ovata vel anguste ovata, 4-8 × 1.5-3.5 cm, apice longe acuminata, basi rotundata , subcordata vel late cuneata, margine serrulata. Inflorescentia terminalis, grandis , glabra vel leviter pilosa ; umbellae 15-25-florae, pedicellis 8-15 mm longis. Fructus (immaturus) globosus, 3-3.5 mm diam., stylis connatis usque ad medium.

TYPUS. — Lowry & Phan Kê Lôc 4925, Vietnam, Lam Dong Prov., along road from Da Lat c. 4 km before village of Da Cháy, moist area near stream crossing in Pinus kremphii forest, 12 o 05’24”N, 108 o 32’33”E, 1530 m, 29 Apr. 1997, fl., y.fr. (holo-, HN (2 sheets)!); iso-, F (5 sheets)!), MO (8 sheets, nos. 4973436, 4973442-444, 5080699-672)!), P (6 sheets).

Prickly treelets, 2-3 m tall. Leaves bipinnate, c. 1 m long, pinnules with 5-17 leaflets; petiole glabrous, with a few scattered prickles; rachises subtended by a pair of accessory leaflets or accessory pinnae at each division; leaflets ovate to narrowly ovate, chartaceous, 4-8 × 1.5-3.5 cm, apex long acuminate, base rounded or slightly subcordate to broadly acute, margins serrulate, lateral veins 8-10 pairs, sparsely pilose along veins above, glabrous below, dark green and shiny above, paler below, petiolules tinged deep purplish brown, 0.5-4 mm long. Inflorescence large with a short main axis, highly branched, axes glabrous to slightly pilose, purplish, with a few scattered prickles; primary branches> 50 cm long, secondary branches 25-40 cm long; bracts and bracteoles persistent, chartaceous, glabrous, lanceolate, margins ciliate, secondary bracts 20- 25 mm long, tertiary ones 10-16 mm long, bracteoles 3-5 mm long; umbels 15-25-flowered; pedicels 8-15 mm long, varying with umbel position (longer on those terminating lower order inflorescence axes), glabrous. Floral buds green. Sepals triangular, 0.6-0.7 × 0.5-0.6 mm. Petals ovate, 2-2.2 × 1.2-1.3 mm. Stamens 5, filaments slender, 3-3.5 mm long; anthers oblong, 0.8- 1 mm long. Ovary 5-locular; styles 5, connate to the middle point. Fruit (immature) globose, 3- 3.5 mm in diam. — Fig. 1.

ETYMOLOGY. — The species epithet honors our friend and colleague NGUYEN Tien Hiep, Coordinator of the MBG-Vietnam Botanical Conservation Program, who has done so much to advance our knowledge of the flora of Vietnam, and who so expertly organizes field expeditions throughout the country.

PHENOLOGY. — Flowering in late April (also with young fruits).

DISTRIBUTION. — Known only from the foothills of Bi Dúp mountain , NE of Da Lat, Lam Dong Prov., Vietnam .

ECOLOGY. — Moist areas near streams; 1450- 1530 m.

PARATYPES. — Lowry & Phan Kê Lôc 4926, Vietnam, Lam Dong Prov., moist area along stream near base camp at village of Klong Lanh , 12 o 08’12”N, 108 o 39’02”E, 1450 m, 29 Apr. 1997, fl., y.fr. ( F!, HN!, MO (4 sheets, nos. 4973434, 4973441, 5080668, 5081752)!) .

Aralia hiepiana resembles A. foliolosa Wall. ex C.B. Clarke from China, India, Bangladesh, northern Thailand, and Vietnam in leaflet shape (ovate to narrowly ovate, with a long acuminate apex and rounded to slightly subcordate base), its small leaflet size, more or less glabrous leaves and inflorescence axes, and small fruits (3-3.5 mm in diam.). The new species differs from A. foliolosa in having bipinnately (vs. tripinnately or quadripinnately) compound leaves, sparsely pilose (vs. glabrous) leaflets along the veins above, serrulate leaflet margins with fine, sharp (vs. rounded) teeth, more numerous (15-25 vs. 7-15) flowers per umbel, longer (8-15 vs. 5-13 mm) pedicels, longer (3-5 vs. 2-3.5 mm) bracteoles, and styles that are connate in the lower half (vs. completely free).

Aralia hiepiana also shares several features with three other Vietnamese species of Aralia : A. armata (Wall.) Seem. , A. chapaensis N.S. Bui , and A. finlaysoniana (Wall. ex G. Don) Seem. , all of which have similar leaflet morphology. The new species can be distinguished from A. armata by its glabrous leaves that are sparsely pilose along the veins above (vs. pilose throughout), inflorescence axes that are slightly pilose (vs. distinctly so), and persistent (vs. caducous) bracts and bracteoles. Aralia hiepiana differs from A. chapaensis in its non-glaucous lower leaflet surface, larger bracteoles (3-5 mm vs. 1.5-2.5 mm long), and partially fused (vs. distinct) styles. Our new species can be easily distinguished from A. finlaysoniana (previously referred to as A. toranensis Ha and A. nguyentaoi Ha in Vietnam; cf. HA 1974, HO 2000, and WEN 2002) in having bipinnately (vs. tripinnately to quadripinnately) compound leaves, only a few scattered, more or less straight prickles on the petioles (vs. more numerous, strongly recurved prickles), leaflets that are only sparsely pilose on the veins above (vs. sparsely strigose throughout) and glabrous below (vs. pubescent to pilose), persistent (vs. caducous) bracts, and umbels with 15-25 (vs. 20-50) flowers.

Figures

Fig. 1. — Aralia hiepiana: A, portion of a leaf; B, infructescence branch; C, flower; D, old flower after shedding of petals; E, young fruit; F, lower leaflet surface showing venation pattern; G, upper leaflet surface showing trichomes on veins (Lowry & Phan Kê Lôc 4925).