Phytotaxa 464 (1): 069–076 ISSN 1179-3155 (print edition) https://www.mapress.com/j/pt/ PHYTOTAXA Copyright © 2020 Magnolia Press Article ISSN 1179-3163 (online edition) https://doi.org/10.11646/phytotaxa.464.1.5 Description of the a species Peliosanthes curviandra (Asparagaceae) from Vietnam with focus on androecium structure and leaf micromorphology NIKOLAY A. VISLOBOKOV1,2,5*, MIKHAIL S. ROMANOV3,6, EVGENIYA A. KUZMICHEVA4,7, SVETLANA P. KUZNETSOVA2,8 & ANDREY N. KUZNETSOV2,4,9 1 Department of higher plants, Biological faculty, M.V. Lomonosov Moscow State University, 1, 12, Leninskie Gory, 119234 Moscow, Russia. 2 Joint Russian-Vietnamese Tropical Scientific and Technological Center, Cau Giay, Hanoi, Vietnam. 3 N.V. Tsitsin Main Botanical Garden of the Russian Academy of Sciences, 4, Botanicheskaya, 127276 Moscow, Russia. 4 A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, 33, Leninsky, 119071 Moscow, Russia. 5 �[email protected]; https://orcid.org/0000-0003-0568-6542 6 �[email protected]; https://orcid.org/0000-0003-1034-4563 7 �[email protected]; https://orcid.org/0000-0001-9916-4109 8 �[email protected]; https://orcid.org/0000-0002-7610-5058 9 �[email protected]; https://orcid.org/0000-0001-5595-1039 *Author for correspondence: �[email protected] Abstract Peliosanthes curviandra is described and illustrated as a new species from southern Vietnam. The new species is characterized by the unusual androecium comprising three erect and curved stamens, perfectly inferior ovary, and a slender tortuous style. The results of observations on the androecium structure and micromorphology of leaf blades were also presented, and the data obtained were briefly discussed in comparison with those known for some other congeners. Keywords: androecium, leaf epidermis, Liriope, Neolourya, Ophiopogon Introduction Peliosanthes Andrews (1808: 605) is a genus of herbaceous plants which inhabit forests of tropical Asia, including part of China and India as well as southeast Asia (Jessop 1976, Averyanov et al. 2015, 2016a, 2016b, Roy et al. 2017a, 2017b, Nong et al. 2019, Taram et al. 2020). Diversity within the genus is a matter of debate: Jessop (1976) considered 33 taxa of Peliosanthes as synonyms of a single species, namely P. teta Andrews (1808: 605). Nevertheless, many safely distinguishable species of Peliosanthes have been recently described (Averyanov et al. 2015, 2016a, 2016b, Vislobokov 2016, Vislobokov et al. 2018). Features of leaf micromorphology can help the identification of species within two genera closely related to Peliosanthes, such as Ophiopogon Ker Gawler (1808: t. 1063) (Cutler 1992) and Liriope Loureiro (1790: 200) (Karpun et al. 2015). We propose that they may be also useful for the identification of closely related species within Peliosanthes, despite being still insufficiently explored. Within Peliosanthes, there is a group of species which were at first described as a separate genus Neolourya Rodriguez (1934: 96): N. weberi Rodriguez (1934: 97), N. pierrei Rodriguez (1934: 97) and N. thailandica Larsen (1966: 196). The main distinguishing feature of these species is a slender tortuous style with the stigma positioned above the level of anthers (Rodriguez 1934). The ovary of Neolourya is completely inferior (Rodriguez 1934), whereas it is half-inferior or superior in many species of the genus Peliosanthes (Averyanov & Tanaka 2012, Vislobokov et al. 2018, Nong et al. 2019). Currently, these species are considered to fall within Peliosanthes (Tanaka 2004, 2019) and were all reduced to synonyms of P. weberi (L.Rodr.) Tanaka (2004: 362). Recently described species P. triandra Aver. & N. Tanaka in Averyanov et al. (2014: 18) and P. choriandra Aver., N. Tanaka & K.S. Nguyen in Averyanov et al. (2017: 699) also belong to this group of species formerly placed under Neolourya. In the present paper, a new species named P. curviandra, which belongs to this group, is described and illustrated. Accepted by Giovanni Astuti: 12 Aug. 2020; published: 14 Oct. 2020 69 Material and methods Living plants as well as herbarium specimens of Peliosanthes were collected within the framework of the Joint Russian- Vietnamese Tropical Scientific and Technological Center in 2019. The plant in question was cultivated in the Main Botanical Garden of the Russian Academy of Sciences (Moscow). All photographs were taken from living plants in cultivation. The description is based on 10–15 measurements of each character performed using a vernier caliper and a ruler under a stereo microscope. For investigation of leaf micromorphology, 18 species of Peliosanthes were examined. The specimens were collected from plants in cultivation in the Main Botanical Garden of the Russian Academy of Sciences (Moscow) and Botanical Institute of the Russian Academy of Sciences (Saint Petersburg) (Table 1). The material was fixed in 70% ethanol and transferred to 100% acetone after passages in 80% and 96% ethanol and a 1:1 mixture of 96% ethanol and 100% acetone. Then the material was dried at the critical-point in a Hitachi HCP-2 critical point drier using liquid carbon dioxide. Dried samples were mounted onto stubs using double-sided sticky tape, coated with gold using an Eiko IB-3 ion-coater and observed using a CamScan 4DV scanning electron microscope (SEM) at Moscow State University (Moscow, Russia). TABLE 1. Traits of abaxial leaf surface of Peliosanthes examined by SEM. Accession number of Greenhouse hosting Abaxial surface of leaf Species Country of origin specimens specimens* epidermis P. argenteostriata Vietnam 1319 BIN smooth P. curviandra Vietnam 19208 MBG smooth P. cambodiana Vietnam 2017.13515 MBG smooth P. cambodiana Cambodia 12608 BIN smooth P. campanulata - 264368 BIN smooth P. densiflora Laos 1317 BIN smooth P. grandiflora Vietnam 712 BIN smooth P. griffithii Vietnam 13393 BIN smooth P. irinae Laos 1304 BIN smooth P. kenhillii Vietnam 13276 BIN smooth P. labroyana - BG18PL01 BIN smooth P. longicoronata Vietnam 1999.13445 MBG smooth P. macrostegia Vietnam 88-48 BIN smooth P. retroflexa Vietnam 9314 BIN smooth P. serrulata Cambodia 12610 BIN slightly rugose P. sinica Vietnam XS14PSP01 MBG finely rugose P. teta Vietnam 13282 BIN smooth P. triandra Cambodia 12609 BIN slightly rugose P. violaceae Thailand 2018.14667 MBG slightly rugose * BIN: Botanical Institute of the Russian Academy of Sciences. MBG: Main Botanical Garden of the Russian Academy of Sciences (MBG). Description of the new species Peliosanthes curviandra Vislobokov, sp. nov. (Figs. 1, 2c) Similar to P. triandra, but filaments not flashy and partly free, also similar to P. choriandra, but with three stamens curved, so that their anthers face down. Type:—VIETNAM, Dong Nai province, Tân Phú district, Cát Tiên National Park, around the point 11° 26.527’, N 107° 25.876’ E, 114 m in elev., in forest, 7 Nov 2019, N.A. Vislobokov 19208 (holotype: MW!). 70 • Phytotaxa 464 (1) © 2020 Magnolia Press VISLOBOKOV ET AL. Herbaceous perennial evergreen plant. Rhizome short plagiotropic or ascending, Ø 4.7–5.8 mm. Cataphylls papyraceous, up to 5.5 cm long. Roots grey, Ø 1.6–3 mm. Foliage leaves dark green, erect, petiolate. Petiole rigid, adaxially sulcate, 23–37 cm long, Ø 2 mm. Lamina lanceolate, basally cuneate and distally acuminate, 15.5–22 cm long, 2.1–3.2 cm wide, glabrous, with 2 main secondary veins on both sides of the midvein. Surface of leaf epidermis smooth. Inflorescence a raceme, 12–13 cm tall; scape erect, 3 cm long, Ø 2.3–2.6 mm, with 5–7 greenish, lanceolate, sterile bract, 10.5–13 mm long, 2.2–3 mm wide; rachis 10 cm long, Ø 1–2.3 mm, bearing about 25 flowers. Floral bracts green, scarious, narrowly lanceolate, 2.7–7.2 mm long, 0.9–2.4 mm wide. Flowers solitary, nutant, almost completely green, basal part (below ovary) ca. 1 mm long, cylindrical, articulated with pedicel. Pedicel 5.6–7.6 mm long, Ø 0.7–0.9 mm, basally with single narrowly lanceolate bracteole 1.6–2.5 cm long, 0.5–0.7 mm wide. Perigone campanulate, 5.8–7.1 mm long, Ø 4.8–5.5 mm; tube light green on both sides, 2.4–3.3 mm long, Ø 1.7–2.3 mm; lobes 6, arranged in two whorls, equal, light green on both sides, broadly ovate, distally acuminate, 3.1–4.2 mm long, 2.1–2.8 mm wide. Stamens 6, arranged in two whorls, on the radii of tepals; filaments green, flat, fused at the base, forming stamen ring 1.8–2 mm high, Ø 2.5–2.9 mm, free part 0.8–1 mm long and wide, filaments at the radii of inner tepals erect, filaments at the radii of outer tepals incurved so that anthers facing downward inside stamen tube; anthers small, yellowish, 0.8–0.9 mm long, introrse. Style light green, cylindrical, slightly tortuous, 1.9–2.5 mm long, Ø 0.3–0.5 mm. Stigma small, as wide as style, positioned above level of anthers of outer whorl. Ovary inferior, obconic, 3-locular, 1.5–1.9 mm high. Fruits unknown. Additional specimens examined:—Living plant in the Main Botanic Garden of Russian Academy of Sciences (Moscow), garden number: 2019.15599, collected from the type locality on 7 Nov 2019. Reproductive organs in spirit of the plant collected from the type locality on 7 Nov 2019, N.A. Vislobokov 19210. Etymology:—The specific epithet refers to the unique structure of its androecium, consisting of six stamens, three of which are curved down with their anthers entirely hidden inside the coronal chamber. Flowering:—Early March in greenhouse. Fruiting:—November in the habitat. Distribution:—Currently known only from the type locality. Taxonomic relationships:—Peliosanthes curviandra resembles those species formerly placed under Neolourya in general structure of flower, but can be distinguished by the androecium made by six partly free stamens, with only three of them erect with exposed anthers, whereas the other three are curved downward and their anthers face inside the staminal tube.