Peliosanthes divaricatanthera Tanaka (2004: 157)

Averyanov, Leonid V., Nguyen, Van Canh, Tanaka, Noriyuki, Nguyen, Khang Sinh & Maisak, Tatiana V., 2023, Three new taxa and two noteworthy species of Peliosanthes (Asparagaceae, Convallarioideae) from Laos and Vietnam, Phytotaxa 609 (3), pp. 209-221 : 212-215

Peliosanthes divaricatanthera Tanaka (2004: 157) ( Fig. 2 )

Type: — VIETNAM. Annam: Tourane [presently Da Nang City], Mt. Bana , 10–22 August 1927. J & M. S. Clements s.n. (holotype in UC: UC-340165!) .

Description:— Herb terrestrial, rhizomatous, acaulescent, evergreen perennial. Rhizome plagiotropic, horizontal or ascending, simple or poorly branching, 1–2.5(3) cm long, (3.5)4–5(5.5) mm in diameter, covered with few remnants of papyraceous pale yellowish-brown bracts, bearing wiry rigid pale brownish roots. Stem ascending or erect, (1)1.5(2) cm high, covered with few sheathing bracts; sheathing bracts, papyraceous white to yellowish, linear or lanceolate, up to 4 cm long, (3)3.5–4(5) mm wide (when flattened). Leaves (18)20–28(30) cm long; petiole rigid, stout, erect, straight, sometimes arcuate, (7.5)9–14(16) cm long; leaf blade (narrowly) elliptic, (9)10–14(16) cm long, (2.8)3–3.8(4.2) cm wide, acute to shortly acuminate, leathery, glabrous, adaxially grass green, abaxially pale green, with (7)8–11(13) longitudinal veins; secondary transverse veinlets numerous, closely spaced, more or less parallel, perpendicular to slightly oblique to longitudinal veins. Flowering stem (including peduncle and inflorescence rachis) bearing a lax reduced thyrse of many small flowers, (22)25–30(32) cm long, shorter than leaves; peduncle dark dirty green to violet, erect, slender, often curved or somewhat flexuose, (16)18–22(24) cm long, (1.8)2(2.2) mm in diameter, bearing 3–8 sparsely arranged bracts that are narrowly triangular, long acuminate, pale green, (5)6–8(10) mm long, 1.5–2 mm wide; basal portion of peduncle with 2–3(4) sheathing bracts that are linear to lanceolate, whitish, papyraceous, (1.5)2–2.5(3) cm long, (2.5)3–4(4.5) mm wide at the base; rachis (8)10–12(14) cm long, with somewhat sparsely arranged fascicled flowers. Floral bracts 2 (outer bract and inner bracteole), light green, herbaceous, narrowly triangular lanceolate or subulate, antrorse, proximal bracts (5)6–8(9) mm long, (0.7)0.9–1.6(1.8) mm wide; bracteole three times smaller; both bracts and bracteoles becoming smaller toward apex of rachis, and those in distal portion of rachis almost rudimental and less than 0.5 mm long. Flowers blooming acropetally, 1–2(3) in axils of primary bracts, ascending, campanulate, (1.6)1.7–1.8(2) mm high, (3.6)3.8–4(4.2) (when flattened 4.4–5.2) mm in diameter. Pedicel ascending, terete, (0.8)1–1.8(2) mm long, dull green or pale violet. Perianth distally 6 - cleft, dull (whitish or grayish) blue-green; tube crateriform, (0.5)0.6(0.7) mm high, (1)1.2–1.4(1.5) mm in diameter; segments 6 in 2 whorls of 3, ovate, (1.7)1.8–1.9(2) mm long, (1.3)1.4–1.5(1.6) mm wide, obtuse, laterally revolute (segments hence look triangular), fleshy. Corona annular, orbicular or obtusely hexagonal in outline, (0.5)0.6(0.7) mm high, (1.9)2–2.1(2.2) mm in diameter, dull blue-green, fleshy, externally convexly slightly incurved toward apex, narrowly ledged near apex of internal corona wall, apex nearly entire, opening nearly orbicular, (1.3)1.4–1.5(1.6) mm in diameter. Anthers 6, sessile, on narrow ledge near apex of corona, thecae horizontally divaricate with ventral sides facing upside (floral front), each theca (sub)circular when viewed from floral front, dull pale beige, (0.9)1–1.2(1.3) mm wide; pollen cream-white. Pistil half-inferior, free part broadly conoid, 0.7–0.8 mm high, (1.3)1.4(1.5) mm across at base, with slight longitudinal ridges radially decurrent from stigmas, slightly 3-sulcate, dull (dark) blue, 3-radially striped with pale dull green; ovary internally incompletely 3-septate, each locule containing 1–2 ovules on central basal placentae; stigma 3-dissected, lobes narrowly obovate, ca. 0.15 mm long. Young seeds narrowly obovoid, green, glossy.

Specimens examined: — CHINA. Yunnan Province: Env.de Yunnan-fu, June 1908, native collector7210, in Herbier de Ch. d’Alleizette (paratype in L: L0068854 https://data.biodiversitydata.nl/naturalis/specimen/ L %20%200068854) . VIETNAM. Dak Lak Province: Lak District, secondary bamboo forest at elevation of 500–600 m a.s.l., March 2022, V. C. Nguyen s.n., herbarium specimen prepared from cultivated plants, 18 February 2023, V. C. Nguyen, L. Averyanov, AL 2039 — LE: LE01170445 (https://en.herbariumle.ru/?t=occ&id=167888) . Photos of the cultivated plants used for preparing the voucher herbarium specimen— LE: LE01123814 (https://en.herbariumle.ru/?t=occ&id=165103) .

Holotype of Peliosanthes tonkinensis examined for comparison: — VIETNAM. Tonkin: Forêts au nord d’Ouonbi [Uông Bí City, Quang Ninh Province], Novembre 1885, B. Balansa 280 ( K: K000099379 http://apps.kew. org/herbcat/getImage.do?imageBarcode= K000099379 ).

Ecology and phenology: —Present material occurs in secondary bamboo forest at elevation of 500–600 m a.s.l. Flowering in January–March. Flowering specimens from Yunnan in China and Da Nang City ( Mt. Bana ) in Vietnam were collected in June and August respectively.

Conservation status: —Only a few mature individuals were found in the type locality. With no detailed information on the occurrence, the conservation status of the new species is estimated as “Data Deficient” (DD), following the guidelines in IUCN (2022).

Distribution: — Vietnam, Dak Lak Province (Lak District), Da Nang City. China, Yunnan Province.

Notes: —In having such traits as leaf blades with nearly parallel, closely spaced transverse veinlets and a lax thyrsoid of small ascending fascicled flowers, Peliosanthes divaricatanthera appears closest to P. tonkinensis Wang & Tang (1936: 83) described from northern Vietnam. P. divaricatanthera differs from P. tonkinensis mainly by the anthers situated on a narrow inward ledge near the apex (vs. apical inside) of the corona, thecae horizontally divaricate with their ventral sides facing upside (floral front) (vs. thecae axially collateral with their ventral sides turned more or less inward), and broadly (or depressed) conic pistil (vs. pistil distally concavely tapering into a distinct style).

Peliosanthes tonkinensis agrees in many respects with P. teta Andrews (1810 : t. 605) and was treated as a synonym of the latter by Jessop (1976) and Wang & Tang (1978). P. tonkinensis is, however, readily distinguishable from P. teta by its smaller flowers, and hence provisionally treated here as a distinct entity. We need to further study the relationship between the two species based on more materials.

Since the horizontally divaricate thecae are apparently apomorphic(vs.axially collateral thecae), P.divaricatanthera with this character state is viewed as an advanced species diverged from the ancestor of P. tonkinensis or of a similar small flowered form of P. teta .

The previous collections of P. divaricatanthera from Vietnam (holotype) and China (paratype) were made in 1927 and 1908, respectively. Namely, Van Canh Nguyen’s rediscovery of the plant in Vietnam (in 2022) was made after 95 years from the second collection (1927).

Figures

FIGURE 2. Peliosanthes divaricatanthera. A. Flowering plants in culture. B. Leaves and inflorescences detached. C. Portion of inflorescence. D. Close up of inflorescence portion. E. Flowers, front view. F. Flower in late anthesis, front view. G. Flower with pedicel, rear view. H. Flowers, rear view. I. Flowers, side view. J. Flowers with basal part removed, rear view. K. Flower, longitudinally sectioned. Photos, photo correction, and plate design by L. Averyanov and T. Maisak, specimen V.C. Nguyen, L. Averyanov, AL 2039.