Peliosanthes luteoviridis Vislobokov, K.S.Nguyen, Kalyuzhny, Nuraliev & N.Tanaka, 2022

Ya. Vislobokov, Romanov, Mikhail S., Nguyen, Khang Sinh, Pham, Vanthe, Pham, Thi Thanh Dat, Nguyen, Van Canh, Тanaka, Noriyuki, Kalyuzhny, Sergey S., Kuznetsova, Svetlana P., Kuznetsov, Andrey N. & Nuraliev, Maxim S., 2022, Peliosanthes luteoviridis (Asparagaceae), a new species with yellowish green flowers from southern Vietnam, Phytotaxa 538 (3), pp. 234-240 : 235-238

Peliosanthes luteoviridis Vislobokov, K.S.Nguyen, Kalyuzhny, Nuraliev & N.Tanaka , sp. nov. ( Figs. 1 , 2 )

Diagnosis:— Most similar to P. macrostegia , but differs mainly by shorter and denser inflorescence, terete peduncle, and yellowish green flowers with a somewhat thinner, translucent perigone.

Type:— VIETNAM. Dong Nai Province: Tan Phu district, Cat Tien National Park , around the point 11°25.523’N, 107°25.722’E, elev. 127 m, in forest, collected in nature on 6 November 2019 by N.A. Vislobokov, the herbarium specimen prepared from the living cultivated plant on 19 May 2021, N.A. Vislobokov, M.S. Romanov 19203H (holotype MW: MW0595759) .

Plant herbaceous, evergreen, perennial, entirely glabrous. Rhizome plagiotropic or ascending, about 2 cm long, 4–6 mm in diameter. Cataphylls chartaceous, 3–7.5 cm long, 6–11 mm wide. Roots grey, 1.5–3.5 mm in diameter. Foliage leaves green, petiolate, ascending or arching. Petiole rigid, adaxially sulcate, 17–36 cm long, 1.3–2.6 mm in diameter. Leaf blade elliptic, 14.5–23 cm long, 2.3–5.2 cm wide, base cuneate, apex acuminate, margin entire, with 9–17prominent longitudinal veins and numerous subtransversal secondary veinlets. Inflorescence a raceme (flowers solitary), about 8.5 cm tall. Peduncle yellowish white, erect, smooth, terete (non-ribbed), 2.1–5 cm long, 2.9–3.7 mm in diameter, with 5–6 sterile bracts; sterile bracts greenish white, lanceolate to narrowly lanceolate, 8.5–15 mm long, 1.8–5 mm wide. Rachis yellowish white, 4.2–6 cm long, 2.2–3.6 mm in diameter, bearing about 35–40 flowers. Flower-subtending bracts greenish white, scarious, lanceolate to narrowly lanceolate, 3.9–9 mm long, 1.5–2.8 mm wide. Flowers densely arranged, touching each other with tepals, facing horizontally or ascending, light yellowish green with darker tepal apices and paler androecial corona-like structure. Pedicel 0.7–1.4 mm long, 0.6–1 mm in diameter. Bracteole single, attached at pedicel base, transversal, lanceolate, 1.6–2 mm long, 0.5–1 mm wide. Perigone campanulate, 4.2–5.8 mm long (including hypanthium), 5.4–9.2 mm in diameter when full open; hypanthium (perigone tube) 1.7–2.8 mm long, 3.0– 3.9 mm in diameter; lobes 6, arranged in two whorls, homomorphic, outer lobes slightly overlapping inner lobes, erect to slightly spreading, slightly translucent, ovate, with margins strongly bent longitudinally on abaxial side, 3–3.7 mm long, 1.9–2.6 mm wide. Stamens 6; filaments united forming fleshy broadly dome-shaped corona-like structure 0.9–1.3 mm high, 3.0– 3.9 mm in diameter with obtusely star-shaped orifice 1.2–1.6 mm in diameter; anthers 6, in radii of tepals, sessile, dorsally attached to upper portion of corona (just below orifice), 0.5–0.6 mm long, introrse. Pistil 1.6–2.2 mm high. Ovary semi-inferior to almost superior, rounded and slightly 3-lobed in top view, 3-locular, 1.3–1.6 mm high, 1.6–1.9 mm in diameter, each locule bearing 4 ovules. Style conoid, 0.2–0.8 mm high, bearing at top 3 flat horseshoe-shaped stigmas 0.3–0.4 mm in diameter. Seeds (unripe) pale green, ovoid, 10.6–12.5 mm long, 6.9–7.5 mm in diameter.

Additional specimens examined (paratypes):— VIETNAM. Dong Nai Province: Tan Phu District, Cat Tien National Park , in forest, 11°25.523’N, 107°25.722’E, elev. 127 m, 6 November 2019 , N.A. Vislobokov 19203 (sterile) (MW: MW0595761); Dong Nai Province: Tan Phu District, Cat Tien National Park , forest with Dipterocarpus sp. , Calamus sp. and bamboo, 11.47958°N, 107.37956°E, elev. 184 m, 2 February 2021 , S.S. Kalyuzhny s.n. (with flowers) (MHA); Dong Nai Province: Tan Phu district, Cat Tien National Park , humid areas under the evergreen broad-leaved forest with Dipterocarpus spp. , 11°26’36”N, 107°25’56”E, about 100 m a.s.l., 9 January 2021 , Pham Thi Thanh Dat, Nguyen Van Canh PTTD 21 (with flowers) (HN); Dong Nai Province: Tan Phu, Dac Lua Commune, Cat Tien National Park , remnants of primary tropical evergreen and semi-deciduous broad-leaved lowland forests on mainly basaltic rocks, 11°30’12”N, 107°17’28”E, 190 m a.s.l., 10 September 2020 , Nguyen Sinh Khang, Pham Van The, Pham Thi Thanh Dat NSK 1354B-1 (with fruits) (HN); same location, the herbarium specimen prepared from the living cultivated plant on 30 January 2021 , Nguyen Sinh Khang NSK 1354B-2 (with flowers) (HN); living plant in the Main Botanical Garden of the Russian Academy of Sciences (Moscow), garden number: 2019.15598, collected by N.A. Vislobokov at the type locality on 6 November 2019 .

Etymology:— The specific epithet refers to the yellowish green floral colour.

Phenology:— Flowering from January to February, fruiting in September.

Distribution:— The species is known only from Cat Tien National Park (Dong Nai Province, Vietnam). It grows at elevations of 100–200 m a.s.l.

Taxonomic relationships: —In having campanulate perigone, androecium forming a dome-shaped corona and semi-inferior to almost superior ovary, the new species is similar to P. macrostegia Hance (1885: 328) and P. crassicoronata K.S.Nguyen, Aver. & N.Tanaka in Nguyen et al. (2020: 41). Peliosanthes luteoviridis differs from P. macrostegia mainly by shorter and denser inflorescence (about 8.5 cm vs. 9–25 cm long), smooth terete (vs. ribbed) peduncle, shorter pedicel (0.7–1.4 mm vs. 5–6 mm long) and entirely yellowish green (vs. green to purple) flower ( Chen & Tamura 2000, Averyanov et al. 2016a). The new species is distinguishable from P. crassicoronata chiefly by its shorter petiole (17–36 cm vs. 50–54 cm long), shorter leaf blade (14.5–23 cm vs. 35–38 cm long), shorter inflorescence (about 8.5 cm vs. 11.5–22.5 cm long), shorter pedicel (0.7–1.4 mm vs. 1.5–3 mm long), smaller (5.4–9.2 mm vs. 10–11 mm in diameter) entirely yellowish green (vs. purple to dark violet) flower, and pistil abruptly tapering to a conoid style (vs. with indistinct style) ( Nguyen et al. 2020). In addition, the somewhat thinner, translucent perigone distinguishes P. luteoviridis from the two similar species.

In its yellowish green flowers forming a dense erect inflorescence, Peliosanthes luteoviridis is superficially somewhat similar to P. cupuliformis Aver., N.Tanaka & K.S.Nguyen in Averyanov et al. (2020b: 2), P. densiflora Aver. & N.Tanaka in Averyanov et al. (2015: 32) and P. separata Vislobokov (2016: 186) . However, the new species is readily distinctive from all of them in floral structure. For instance, the stamens of P. luteoviridis form a dome-shaped hemispherical corona partly covering the pistil, whereas the staminal corona of P. cupuliformis is annular and widely open ( Averyanov et al. 2020b); the flowers of P. luteoviridis are smaller than those of P. densiflora (5.4–9.2 mm vs. 10–12 mm in diameter) ( Averyanov et al. 2015); the staminal corona of P. luteoviridis is only shallowly lobed apically, whereas that of P. separata is dissected nearly to the base ( Vislobokov 2016).

Peliosanthes luteoviridis inhabits forests of Cat Tien National Park (Dong Nai Province, Vetnam), where it cooccurs with P. curviandra Vislobokov in Vislobokov et al. (2020: 70). Since the vegetative parts of the two species (as well as a significant portion of other species of the genus) look somewhat alike, these species can be confused if encountered in a sterile condition. With respect to the floral characters, P. luteoviridis is clearly distinguished from P. curviandra by semi-inferior to almost superior ovary and a shorter conoid style, whereas the latter species possesses inferior ovary and a long slender tortuous style characteristic of the species complex formerly recognized as the genus Neolourya Rodriguez (1934: 96) .

Figures

FIGURE 1. Peliosanthes luteoviridis. A. Habit. B. Foliage leaf, adaxial view. C. Inflorescences. D, E. Portions of inflorescence. F. Flower, side view. G. Flower, longitudinal section. Photos:A, B by N.A. Vislobokov from Vislobokov 19203; C‒G by M.S. Romanov from 2019.15598; correction and design by N.A. Vislobokov.

FIGURE 2. Peliosanthes luteoviridis. A. Habit. B, C. Part of foliage leaf, adaxial (B) and abaxial (C) views. D. Fruiting inflorescence (showing seeds). E. Flower, view from below. F. Flower, top view. G, H. Inflorescences. I. Portion of inflorescence. Photos by T.T.D. Pham & K.S. Nguyen from Nguyen Sinh Khang et al. NSK 1354B-1, NSK 1354B-2; correction and design by N. Vislobokov.