Peliosanthes laotica Vislobokov, Nuraliev & N.Tanaka, 2023

Vislobokov, Nikolay A., Romanov, Mikhail S., Тanaka, Noriyuki & Nuraliev, Maxim S., 2023, Peliosanthes laotica (Asparagaceae), a new narrow-leaved species from Laos, Phytotaxa 609 (2), pp. 151-156 : 152-153

Peliosanthes laotica Vislobokov, Nuraliev & N.Tanaka , sp. nov. ( Figs. 1 , 2 )

Diagnosis:— Most similar to P. cupuliformis , but differs by longer narrowly elliptic to lanceolate leaf blade, and longer and wider pedicellate flowers with obconic ovary higher than 1 mm.

Type:— LAOS. Bolikhamsai province: Thaphabat district, Phou Khao Khouay National Biodiversity Conservation Area, near Tad Xai waterfall, rainforest, elev. 300 m, 18° 27’ 6.3’’ N, 103° 8’ 39.7’’ E, collected in nature on 9 December 2015 by N. A. Vislobokov , the herbarium specimen prepared from the living cultivated plant (garden number: 2015.11335) on 1 June 2023, M. S. Romanov 2301 (holotype MW: MW0595839 ) .

Additional specimens examined (paratype):— LAOS. Bolikhamsai province: Thaphabat district, Phou Khao Khouay National Biodiversity Conservation Area, near Tad Xai waterfall, rainforest, elev. 300 m, 18° 27’ 6.3’’ N, 103° 8’ 39.7’’ E, 9 December 2015, N. A. Vislobokov 15041 ( MW: MW0751736 ) .

Specimen in living collection: — Living plant from the same gathering as the paratype (Vislobokov 15041), cultivated in the Main Botanical Garden of the Russian Academy of Sciences (Moscow), garden number: 2015.11335 .

Description: — Plant herbaceous, evergreen, perennial, entirely glabrous. Rhizome plagiotropic or ascending, 2.2– 3.9 mm in diameter. Cataphylls chartaceous, 2.6–5.2 cm long, 8–9 mm wide. Roots grey, 1.5–2 mm in diameter. Foliage leaves green, petiolate, ascending or arching. Petiole rigid, adaxially sulcate, 10.5–17 cm long, 1–1.7 mm in diameter. Leaf blade narrowly elliptic to lanceolate, 12–15.5 cm long, 1.3–1.9 cm wide, base narrowly cuneate, apex acuminate, margin entire, with 6–9 longitudinal veins prominent on both sides. Inflorescence a raceme, about 4.5 cm long. Peduncle violet with green dots, erect, terete, c. 1 cm long, 1.7–2 mm in diameter, with 1–2 sterile bracts; sterile bracts green with violet dots along margin, lanceolate to narrowly lanceolate, 9–10 mm long, 1.5–2 mm wide. Rachis violet with green dots, 2.8–3.3 cm long, 1.3–1.7 mm in diameter, bearing about 15–17 flowers. Flower-subtending bracts pale green, scarious, lanceolate to narrowly lanceolate, 4.1–6.6 mm long, 1.3–2.1 mm wide. Flowers solitary in bract axils, facing horizontally or ascending. Pedicel violet with green dots, 1.3–2.1 mm long, 0.6–0.7 mm in diameter, articulated with ovary. Bracteole single, attached at pedicel base, transversal, pale green, scarious, lanceolate, 1.7–2.6 mm long, 0.5–0.8 mm wide. Perianth widely campanulate (saucer-like), 5.7–7.6 mm in diameter when fully open; perianth tube pale green, vanishingly short (up to c. 1.5 mm long), 2.1–2.5 mm in diameter; lobes 6, arranged in two whorls, homomorphic, pale green with violet margin on both sides, erect to slightly spreading, ovate, with margins slightly bent longitudinally on abaxial side, 1.7–2.5 mm long, 1.2–1.7 mm wide. Stamens 6; filaments united forming corona-like structure; corona-like structure pale green outside, violet mottled inside, fleshy, ring-shaped, round to obtusely hexagonal outside, inside with prominent broad protrusions towards flower centre in radii of tepals, 0.2–0.3 mm high, 2.8–3.2 mm in diameter; anthers 6, in radii of tepals, sessile, dorsally attached to upper portion of corona-like structure, 0.1–0.2 mm long, introrse. Ovary semi-inferior to almost inferior, pale green, obconic, 3-locular, 1.7–1.8 mm high, 2.1–2.5 mm in diameter. Style dark violet, conical, 3-lobed in top view, 0.5 mm high, 0.6–0.7 mm in diameter, bearing at top 3-lobed stigma 0.1 mm in diameter. Fruits unknown.

Etymology:— The specific epithet refers to the country of the type locality.

Phenology:— Flowering during June in cultivation.

Distribution:— The species is known only from type locality.

Taxonomic relationships: —In its flower structure, the new species is somewhat similar to P. cupuliformis Aver., N.Tanaka & K.S.Nguyen in Averyanov et al. (2020b: 2). Nevertheless, P. laotica differs from P. cupuliformis in petiole 10.5–17 cm (vs 3–8 cm) long, leaf blade narrowly elliptic to lanceolate, 12–15.5 × 1.3–1.9 cm (vs elliptic, 4–7 × 1.4–2.8 cm), pedicellate (vs sessile) flowers, flowers 3.5–4.3 mm long and 5.7–7.6 mm in diameter (vs 2.9–3.3 mm long and 3.8–5.2 mm in diameter), ovary obconic (vs broadly obconic), 1.7–1.8 mm (vs less than 1 mm) high.

In addition, Peliosanthes laotica is similar to P. griffithii Baker (1879: 506) , but differs in leaf blade narrowly elliptic to lanceolate (vs oblanceolate-oblong or elliptic to broadly elliptic), leaf blade 1.3–1.9 cm (vs 2–5.7 cm) wide, pale green (vs dark purple-violet to almost black) perianth, and corona 0.2–0.3 mm (vs 1–1.6 mm) high ( Baker 1879, Averyanov et al. 2016a, Nguyen et al. 2017).

Figures

FIGURE 1. Peliosanthes laotica. A. Habit. B. Foliage leaf, abaxial view. C, D. Inflorescences. E. Portion of inflorescence. F. Flower, longitudinal section. G. Flower, top view. Photos: A by N.A. Vislobokov from nature (Vislobokov 15041); B‒G by M.S. Romanov from cultivated plant (2015.11335); corrections and design by N.A. Vislobokov.

FIGURE 2. Peliosanthes laotica, a paratype specimen Vislobokov 15041 at MW (MW0751736), available at https://depo.msu.ru/open/ public/en/item/MW0751736