Polysopra gioii Lưu, T

Trư ờng, Lưu H ồng, T ịch, Nguy ễn Thi ện & H ợp, Tr ần, 2015, Polyspora gioii (Theaceae), a new species from Vietnam, Phytotaxa 219 (3), pp. 296-300 : 296-299

Polysopra gioii Lưu, T ịch et H. Trần, sp. nov. ( Fig. 1 )

Allied to Polyspora huongiana in having hairy terminal buds, coriaceous leaf laminas, and red campanulate and pedicellate flowers but different in having sparsely yellow stellate and densely white to brown hairs on twigs, leaf petioles and adaxial laminas, obovate laminas, 5–7-lobed stigmas, 5–7-carpellate ovaries and larger capsules.

Type:— VIETNAM. Khánh Hòa Province: Hòn Bà Nature Reserve, 12°07’39”N and 108°57’39”E, at ca. 1,300 m elevation, 11 April 2012, Lưu H ồng Trư ờng, Tr ần Gi ỏi & Nguyễn Thi ện T ịch KH117 (holotype, SGN!; isotypes, HNU!, P!, VNMN!), 18 May 2012, Lưu H ồng Trường & Trần Giỏi KH118 (paratypes SGN!, MBG!) .

Recommended Vietnamese name:—Đa tử trà Giỏi.

Tree to 10 m high, evergreen, well branched; new shoots yellow stellate and densely white to brown tomentose, stout; branches sparsely yellow stellate and densely white to brown tomentose; young branches green and old branches brown. Leaf petiole curving slightly upwards, falcate, stout, sparsely yellow stellate and densely white to brown tomentose, 11–13 mm long, 4–5 mm wide, up to 3 mm thick; petiole ascending at ca. 45° angle to the midrib; leaf lamina 9–17 cm long, 5–8 cm wide, coriaceous, obovate, convex, adaxially shiny, glabrous except the base of midrib with sparse yellow stellate and dense brown tomentose hairs, light yellowish or brownish green when young, dark green when mature, abaxially sparsely yellow stellate and densely white to brown tomentose, light brown when young, pale green when mature; margins ciliated when young, shallowly toothed and partially revolute; apex obtuse to sub-acute, base cuneate; midrib 2.5–3.2 mm wide proximally, less than 1 mm distally, light brown, adaxially sunken, sparsely yellow stellate and densely tomentose at base, abaxially prominent, sparsely yellow stellate and densely white to brown tomentose; secondary venation pinnate, indistinctly brochidodromous, with 13–16 pairs of veins, adaxially sunken between two slightly raised ridges, abaxially slightly prominent; tertiary venation sparse and indistinct. Flowers subterminal, lacking scent, solitary, sessile, borne on a very short pedicel attached towards the apex at 30° to the stem; pedicel thick, ca. 2 mm long, 5 mm wide, almost hidden by perules, tomentose, green or light brown; flowers dark pink to red, rather fleshy, campanulate, 45–55 mm high and 40–50 mm in diameter; petals six, red, concave, unevenly obovate, glabrous, sometimes emarginate, basally joined for 1–6 mm, otherwise free, arranged in two whorls, the first (outer) whorl of three petals, 30–45 mm long, 22–34 mm wide, slightly concave, slightly asymmetric; the second (inner whorl) of three petals, 45–50 mm long, 30–42 mm wide, slightly concave, slightly asymmetric, obovate; perules 9, spirally arranged, concave, 9–16 mm long, 18–25 mm wide, caducous, proximally yellowish and distally dark pink, inner surface glabrous, outer surface finely tomentose, thin and translucent at margins; stamens not numerous (120– 160), in a circular formation 20–35 mm in diameter, divided into three concentric circles; filaments 2.5–3 cm long, glabrous, basally joined for 2–6 mm, light yellow distally, pinkish proximally but of a lighter colour than petals, basally joined to the inner petal whorl for 4–10 mm; anthers glabrous, bright yellow, later dark yellow to brown, 2.5–3 mm long, about 1.5 mm wide, dorsifixed, acuminate at the distal end, very slightly cordate at proximal end; style columnar, 28–30 mm long, proximally thick, consisting of 3–5 seamlessly fused parts, style greenish yellow, entirely finely hairy for about basal two thirds of its length, glabrous at the top, stigma divided distally for 1–2 mm into 5–7 rather indistinct apical lobes of greenish yellow colour; ovary superior, resting on a hard woody base, oval, lightly striated, 5–7-carpellate, brownish to pinkish yellow, densely tomentose, 9–10 mm long, 9–10 mm wide; juvenile seed capsules ovoid, light green, with indistinct, unevenly distributed striations, densely tomentose, with distinct mucronate apex, basal scars present from the caducous perules; mature seed capsule ovoid, reddish brown, sparsely yellow stellate and densely brown tomentose, woody and hard, 40–50 mm long, 22–24 mm in diameter, 5–7-valved, each valve containing 5 seeds; columella persistent, 40–43 mm long; seed mid brown, glabrous, longitudinally compressed, together with a wing 19–22 mm long and 4–6 mm wide; wing thin, roughly ellipsoid.

Habitat:— P. gioii is found in broad-leaved evergreen forests on fertile soils. Flowers were seen in February to April and fruits in April to May.

Distribution & IUCN preliminary assessment: —The species is very rare; only one population of fewer than 50 mature individuals is known from the type locality. The species has an estimated extent of occurrence much less than 100 km 2 and its unique population was partially destroyed by the road connecting the base and the summit of Hon Ba Mountain. Given this situation, this species should be considered for placement in the Critically Endangered category, CR B1a&b(iii) and/or D ( IUCN, 2001).

Etymology:—Named after Mr. Trần Giỏi, the forester who first discovered the species.

Notes: — P. gioii appears to be closest to P. huongiana as both species share the following morphological characteristics: tree up to 10 m high with hairy terminal buds, coriaceous leaf lamina and, especially, red campanulate and shortly pedicellate flowers. However, the new species is readily distinguishable from the latter by several key differences as shown in Table 1. The combination of sparse yellow stellate and dense white to brown hairs on twigs, petioles and abaxial laminas, obovate laminas and red campanulate flowers in P. gioii makes it distinct from all the other known species of Polyspora .

Based on the available literature ( Pitard, 1902; Gagnepain, 1941; Keng, 1972; Krüssmann, 1985; Pham-hoang, 1999; Bartholomew & Ming, 2005; Ming & Bartholomew, 2007; Orel et al., 2012 Orel et al., 2013) and the authors’ field observations, the known Vietnamese species of Polyspora can be distinguished by the following key:

1 Flowers dark pink or red.....................................................................................................................................................................2

- Flowers yellow or white .....................................................................................................................................................................3

2. Leaves narrowly elliptic to elliptic, glabrous .................................................................................................................. P. huongiana

- Leaves obovate, abaxially sparsely stellate and densely tomentose......................................................................................... P. gioii

3. Flowers yellow .................................................................................................................................................................. P. balansae

- Flowers white .....................................................................................................................................................................................4

4. Ovaries 7-locular and capsules 60–70 mm long, 7-valved............................................................................................ P. gigantiflora

- Ovaries 3–5-locular and capsules 20-50 mm long, 3–5-valved .........................................................................................................5

5. Trees up to 25 m .................................................................................................................................................................................6

- Trees up to 12 m .................................................................................................................................................................................7

6. Petals 6–7, filaments hairy at basal 1/2, ovaries 5-locular, styles 17–18 mm long...................................................... P. bidoupensis

- Petals 5, filaments glabrous, ovaries 4–5-locular, styles 25–30 mm long.............................................................................. P. ampla

7. Leaf apex acuminate, leaf base acute, pedicels almost absent, ovary 3-locular, styles 3-sulcate ...................................... P. intricata

- Leaf apex obtuse or emarginate, leaf base cuneate, pedicels present, ovary 3–5-locular, styles 3–5-sulcate....................................8

8. Trees up to 4 m high, leaf lamina narrowly elliptic to elliptic, leaf apex acute or cuspidate, pedicels 7–12 mm long........... P. nivea

- Trees 7–12 m high, leaf lamina oblong to oblanceolate to obovate, leaf apex obtuse to emarginated, pedicels up to 5 mm long....9

9. Capsules 40 mm long ......................................................................................................................................................... P. axillaris

- Capsules 20 mm long ..................................................................................................................................................... P. tonkinensis

Figures

FIGURE 1. Polyspora gioii.A. Young twig. B. Vegetative bud. C. Leaf, adaxial surface. D. Leaf, abaxial surface. E. Leaf apex. F. Stellate and tomentose hairs on abaxial lamina. G. Flower, side view. H. Flower, top view. I. Perules. J. Style and stigma. K. Ovary. L. Petals and stamens. M. Capsule. N. Seeds. Photos by Lưu Hồng Trường.