Peliosanthes densiflora Aver. & N.Tanaka, 2015

Averyanov, Leonid V., Tanaka, Noriyuki, Nguyen, Khang Sinh, Nguyen, Hiep Tien & Konstantinov, Eugene L., 2015, New species of Ophiopogon Ker Gawl., Peliosanthes Andrews and Tupistra Ker Gawl. (Asparagaceae) in the flora of Laos and Vietnam, Adansonia 37 (1), pp. 25-45 : 32-38

Peliosanthes densiflora Aver. & N.Tanaka , sp. nov.

( Figs 5 ; 6 )

Haec species nova Peliosanthi violaceae Wall. ex Baker var. violaceae et var. princepti Baker subsimilis est, sed ab eis bractea floris ascendenti et breviter distanti e base floris, bracteola juxta basem floris locata, floribus sessilibus cum segmentis perianthii magis valde expansis, et coronis albis est distincta.

TYPUS. — Laos. Vientiane province, 13 km to the NNW of Kasi town along new road to Luang Prabang, on slope of Nam Pong Gnai River , around point 19°21.978’N, 102°09.282’E at elev. about 827 m a.s.l., 22.X.2013 , E. Konstantinov , K 141 (holo-, LE!) . ETYMOLOGY. — The specific epithet refers to the compact inflorescence dense with many flowers.

HABITAT AND PHENOLOGY. — Primary and secondary dry broadleaved evergreen and deciduous forests, usually co-dominated by Tetrameles nudiflora R.Br. , Pometia eximia Bedd. , Croton argyratus Blume , Arenga westerhoutii Griff. and Ficus religlosa L., on highly eroded rocky marble-like limestone and shale at elevations 300- 900 m a.s.l., common on shady mountain slopes, rocky outcrops and cliffs in rather humid conditions. Flowers in November-December, fruits in December-January. Locally common. Expected IUCN Red List status – LC.

DISTRIBUTION. — Laos (Vientiane province, Vang Vieng and Kasi districts). Endemic of northern Laos.

MATERIAL EXAMINED (PARATYPI). — Laos. Vientiane province, Vang Vieng district, Nathong village, about 5 km to the W of Vang Vieng town, Tham Kang Mt., around point 18°55’51.4”N, 102°23’50.6”E, dry broad-leaved primary and secondary evergreen forest on very steep rocky slopes and on vertical cliffs of remnant highly eroded rocky limestone mountains composed of solid crystalline limestone at elevations 300-400 m, clustering terrestrial and lithophytic herb with erect to suberect, ramose rhizome on steep rocky slope, leaves to 80 cm long, petiole 30-45 cm long, leaf blade glossy uniformly green on both sides 25-35 cm long, 6-10 cm wide, not rare, 14.III.2013, N. T.Hiep, L.Averyanov, N. S.Khang, P. V.The, S.Lorphengsy, LA-VN 421 ( CPC! LE!). — Vientiane province, Vang Vieng district, Phol Xai village, about 8 km to the W of Vang Vieng town, Phar Poon Mt., around point 18°56’11.5”N, 102°20’05.0”E, dry broad-leaved primary and secondary evergreen forest on very steep rocky slopes and on vertical cliffs of remnant highly eroded rocky limestone mountains composed of solid crystalline limestone at elevations 300-900 m, terrestrial clustering herb with ramose rhizome in shady place, leaves glossy light green on both sides, common at elevations 300-800 m, 15.III.2013, N. T.Hiep, L.Averyanov, N. S.Khang, P. V.The, S.Lorphengsy, LA -VN 433 ( CPC! LE!). — Vientiane province, Kasi district, Thong Mout village, Num Pong Mt., around point 19°21’46.9”N, 102°09’29.8”E, primary and second- ary broad-leaved evergreen forest on steep shale slopes along stream at elevation about 900 m, terrestrial herb with leaves to 1 m long, petiole 30-40 cm, leaf blade glossy uniformly green on both sides, 14-18 cm long, 7-10 cm wide, not rare, 22.III.2013, L.Averyanov, N. S.Khang, S.Lorphengsy, LA -VN 722 ( CPC!, LE!). — Vientiane province, Kasi district, in the vicinity of Khuang Lang Cave around point 19°18.198’N, 102°09.031’E, dry semi-deciduous forest with Tetrameles nudiflora , Pometia eximia , Croton argyratus , Arenga westerhoutii , Ficus religiosa on stream slope at elev. about 631 m a.s.l., E.Konstantinov, K 103 ( LE!). — Vientiane province, 13 km to the NNW of Kasi town along new road to Luang Prabang, on slope of Nam Pong Gnai River, around point 19°21.978’N, 102°09.282’E at elev. about 827 m a.s.l., 22.X.2013, E.Konstantinov, K 140 ( LE!). AFFINITIES

This new species somewhat resembles Peliosanthes violacea Wall. ex Baker var. violacea and var. princeps Baker , but is distinct from them by the ascending floral bract shortly distant from the floral base, bracteole located beside the floral base, sessile flowers with more strongly expanded perianth segments, and white coronas.

DESCRIPTION

Terrestrial and lithophytic clustering perennial herb from suberect or ascending, ramose rhizome to 10 cm long, about 0.5-0.8 cm in diam., often apically densely branching, bearing many semi-woody cord-like roots. Stems erect, 1-2 cm tall, covered loosely with broad, papyraceous scaly leaves. Sheath leaves linear-lanceolate, conduplicate, to 18 cm long, 1-1.5 cm wide, fugacious, i.e. soon becoming papyraceous or scarious, eventually disintegrated into fibrous remains. Leaves erect, petiolate, to 0.8 m tall; petiole rigid, curved, shallowly channeled in basal part, 30-45 cm long; blade elliptic, shortly acuminate with obtuse or subacute apex, entire, glabrous, uniformly green and glossy on both sides, (18)22-30(35) cm long, (6.5)7.5-9(10) cm wide; longitudinal veins many, subperpendicularly crossed with many transversal veinlets. Inflorescence a terminal, compact spadix-like spike; peduncle ascending, rigid, (6)8-12(15) cm long, 2.5-3.5 mm in diam., dark green with violet tint, or dark violet to almost black, naked or with 1-2 narrowly deltoid, papyraceous or scarious sterile bract 1-2 cm long, 6-10 mm wide; rachis densely many-flowered, (5)7-12(15) cm long. Floral bracts 2 per flower, antrorse, white, scarious; bract located shortly distant from lower side of flower (proximal bracts distant for 4-7 mm from floral base), cuneate to triangular, (3) 5-8 mm long, (2) 3-4 mm wide; bracteole situated lateral to flower, obliquely broadly triangular, (2.5)3-4(5.5) mm long, (1.5)2- 2.5(3) mm wide. Flowers solitary in bracteal axil, sessile on small knob-like short protuberance (much reduced pedicel), pure white, widely open, (9)10-12(13) mm across; proximal (syntepalous) part cupulate, 3-3.5(4) mm long, 6-7 mm across. Perianth segments subsimilar, triangularly (broadly) ovate, slightly recurved, subobtuse at apex, (2.5) 3-3.5 mm long, 3.5-4.5 mm wide, margins scarious, finely irregularly undulate.Corona indistinctly hexagonal, almost flat, 5.5-6 mm across, 0.5-0.6(1) mm high, the distal orifice 3-subdentate, 2.2-2.6 mm in diam. Anthers 6 on apical inner surface of corona, oblong, introrse, 0.8-1 mm long, sessile, dorsifixed. Ovary subsuperior, broadly conic, 3 mm tall and wide, longitudinally 6-ridged, 3-lobed, the interior partitioned into 3 chambers by 3 septa almost touching along inward edges; each chamber adaxially slightly open with narrow longitudinal slit, containing 4-5 ovules on basal placenta; style indistinct; stigma 3-partite, the lobes narrowly oblanceolate, densely papillulate. Young seeds ovoid, drupe-like, glossy, 8-10 mm long; seed coat fleshy, green, flushed with blue.

REMARKS

Comparatively large white flowers of Peliosanthes densiflora Aver. & N.Tanaka , sp. nov. somewhat resemble the pale greenish ones of P. violacea Wall. ex Baker var. violacea and var. princeps Baker ( Baker 1879) . But, the new species differs in many respects; e.g., the ascending floral bracts lying shortly distant from the floral base, bracteoles lying at the side of the reduced pedicel (vs on the basal part of pedicel), sessile flowers (vs distinctly pedicellate flowers), more strongly spreading perianth segments, and white coronas (vs purplish coronas). The large leaves reaching 0.8 m in height is another characteristic of this species among congeners.

Figures

FIG. 5. — Peliosanthes densiflora Aver. & N.Tanaka, sp. nov.: A, flowering plant; B, inflorescence on peduncle; C, portion of inflorescence with open flowers, D, portion of proximal part of inflorescence with flowers removed, E; floral bract (lower) and bracteole (upper), F; flower, views from rear (upper) and frontal view (lower); G, sagittal sections of flower; H, pistil, frontal view; I, pistil, side views; J, pistil in side view with sagittal section of the frontal locule; K, cross section of ovary in middle part. Drawn from the type E.Konstantinov, K 141 by L.Averyanov. Scale bars: A, 10 cm; B, 5 cm; C, 1 cm; D-H, 5 mm; I-K, 3 mm.

FIG. 6. — Peliosanthes densiflora Aver. & N.Tanaka, sp. nov.: A, flowering plant in natural habitat (type – K 141); B, flowering plant (paratype - K 140); C, D, plant with young spike (type – K 141); E, E’, F, inflorescences and flowers (paratype – K 140). All photos by E.Konstantinov, correction and design by L.Averyanov. Scale bars: B-D, 10 cm; E, 5 cm; E’, 2 cm; F, 5 mm.