Aspidistra sonlaensis N.B. Trinh, V.T.Pham, Nuraliev & Vislobokov, 2021

Trinh, Ngoc Bon, Pham, Van The, Nguyen, Thanh Son, Do, Thi Thanh Ha, Nguyen, Khang Sinh, Anh, Le Tuan, Nuraliev, Maxim S. & Vislobokov, Nikolay A., 2021, Aspidistra sonlaensis (Asparagaceae, Nolinoideae), a new species from northern Vietnam, Phytotaxa 528 (1), pp. 10-18 : 11-15

Aspidistra sonlaensis N.B. Trinh, V.T.Pham, Nuraliev & Vislobokov , sp. nov. ( Fig. 1 , 2 )

Diagnosis: Aspidistra sonlaensis is morphologically similar to A. micrantha , but differs in perigone with 7–8 (vs. 5–6) lobes, anthers inserted at base (vs. at middle) of perigone tube and widely obconic (vs. club-shaped) pistil.

Type:— VIETNAM: Son La Province, Muong La District, Ngoc Chien Commune , along valley of secondary evergreen forest, around point 21°35’58.73”N 104°06’40.82”E, at elevation 1280 m a.s.l., 30 October 2020, Trinh Ngoc Bon, Nguyen Thanh Son, Do Thi Thanh Ha SCU 2020 -01 (holotype VAFS! ; isotype VNMN! ).

Plant perennial, evergreen, herbaceous, rhizomatous, glabrous, 80–150 cm tall. Rhizome creeping, unbranched, dull yellow-green when young, dark brown when mature, with very short internodes, 1.5–2.2 cm in diam. Roots white to grey, 4–6 mm in diam. Rhizomes with regularly repeating units, each unit comprising several distichous cataphylls followed by a single foliage leaf. Cataphylls ovate-oblong, reddish to black-purple, up to 14.5 cm long. Leaves petiolate; petiole stout, erect, white or green at base, green towards apex, adaxially sulcate, 35–80 cm long, 3–8 mm in diam.; lamina green, narrowly elliptic, basally cuneate and attenuate, apically acuminate, 45–80 cm long, 8–15 cm wide, parallel-veined with median vein prominent on abaxial surface, margin entire. Inflorescences axillary, up to 2 per rhizome unit. Peduncle erect, white, green to reddish or black-purple, 6–15 cm long, 3–4 mm in diam., with about 5 distichously arranged bracts. Bracts white, green to reddish or black-purple, broadly deltoid, apex cuspidate, 1–1.5 cm long, 1.5–2.3 cm wide. Flower solitary at top of peduncle. Perigone urceolate, fleshy, shiny, 28–30 mm long; perigone tube shortly ellipsoid in side view to nearly globose, uniformly greenish white or white with reddish tint (especially towards apex) outside, uniformly white inside, 2.1–2.2 cm long, 2–2.1 cm in diam. at widest part; lobes 7–8, apparently in two whorls, erect to spreading, light green or yellowish green on both surfaces and sometimes reddish or purple outside, ovate, thick and fleshy, apex obtuse, 7–8 mm long, 5.5–6.1 mm wide. Stamens 7–8, inserted at base of perigone tube; anthers sessile, appressed to perigone tube, bright yellow, ellipsoid, 3.5–4.5 mm long, 2– 2.4 mm wide, introrse. Pistil uniformly white, widely obconic, ca. 11 mm tall; ovary superior, inconspicuous; style stout, widely obconic, roundish tetragonal in cross section, with numerous longitudinal ridges, ca. 4 mm tall, 3 mm proximally to 15 mm distally in diam.; stigma hemispherical, fleshy, ca. 7 mm tall, 13–15 mm in diam., upper surface smooth with 4 hardly visible irregular radial fissures, undulate at margin. Fruit dark green or sometimes dark purple, globose or obovoid, 2.2–2.5 cm long, 2.3–2.7 cm in diam., surface muricate; seeds 7–8, broadly ovoid to globular, 6.5–15 mm long, 4–7 mm in diam.

Etymology:—The specific epithet “ sonlaensis ” refers to Son La Province, where the new species was found.

Phenology: —Flowering in July–November, fruiting in October–November in nature.

Distribution and ecology:— Aspidistra sonlaensis is only known from Son La Province, Vietnam ( Fig. 3 ). It grows in secondary evergreen forest at elevation of 1280 m. The following plants are recorded as associated with the new species: Selaginella tamariscina (Selaginellaceae) , Angiopteris yunnanensis (Marattiaceae) , Cyathea yunnanensis (Cyatheaceae) , Dicranopteris linearis (Gleicheniaceae) , Pteris semipinnata , Pteris sp. (Pteridaceae) , Tectaria sp. (Tectariaceae) , Lindera rufa (Lauraceae) , Amorphophallus coaetaneus (Araceae) , Calamus tetradactylus (Arecaceae) , Alpinia calcarata (Zingiberaceae) , Cyrtococcum patens (Poaceae) , Altingia yunnanensis (Altingiaceae) , Elatostema balansae (Urticaceae) , Lithocarpus vestitus (Fagaceae) , Betula alnoides (Betulaceae) , Choerospondias axillaris (Anacardiaceae) , Tetradium glabrifolium (Rutaceae) , Schima wallichii (Theaceae) , Alniphyllum eberhardtii (Styracaceae) , Saurauia tristyla (Actinidiaceae) , Lasianthus sp. , Lerchea micrantha , Ophiorrhiza baviensis , Psychotria sp. (Rubiaceae) , Staurogyne sp. (Acanthaceae) , and Ilex sp. (Aquifoliaceae) .

Conservation status: —We encountered a single population of Aspidistra sonlaensis consisting of less than 50 flowering individuals. The population was observed during two seasons, in October 2020 and July 2021. The habitat of A. sonlaensis is protected by Muong La Nature Reserve. Since further comprehensive investigations are needed to estimate the number and size of populations of A. sonlaensis in the area, we here propose a status of ‘Data Deficient’ (DD) for this species according to IUCN categories and criteria ( IUCN 2019).

Taxonomic relationships: —The new species is morphologically close to A. micrantha Vislobokov & Nuraliev in Vislobokov et al. (2019c: 291), but readily differs from the latter in its length of peduncle (6–15 cm vs. 0.4–0.7 cm), size of flower (perigone 28–30 mm vs. 4.4–5.7 mm long), number of perigone lobes (7–8 vs. 5–6), position of anthers (inserted at base vs. at middle of perigone tube), and shape of pistil (widely obconic, with widely obconic style vs. clubshaped, with cylindrical style). The new species is also similar to A. globosa Vislobokov & Nuraliev in Vislobokov et al. (2016: 47) in shape of perigone, but differs in shape and colour of pistil (widely obconic, white vs. club-shaped, purple) and structure of shoot system ( A. sonlaensis possesses creeping rhizome, whereas A. globosa constantly shows erect stem). Finally, A. sonlaensis is somewhat similar to A. minutiflora Stapf (1903: 113) , A. urceolata F.T.Wang & K.Y.Lang in Lang (1981: 381) and A. xichouensis Lei Cai, Z.L.Dao & G.W.Hu in Cai et al. (2020: 145) in shape and colour of perigone ( Liang & Tamura 2000, Cai et al. 2020), but the new species has larger perigone (28–30 mm long, 20–21 mm in diameter vs. 4.5–13 mm long, 4–9 mm in diameter) and can be easily distinguished from all of these species by its narrowly elliptic (vs. lorate to lorate-oblanceolate) leaves 8–15 cm (vs. 1–4 cm) wide.

The differences between the new species and its similar congeners are summarized in Table 1 .

Aspidistra sonlaensis can be attributed to the section Luridae G.Z.Li in Li et al. (2000: 214) because it possesses tetramerous flowers. The new species shows strong differences from all 19 species included by Li et al. (2000) in this section. Among the species indicated above as the most similar ones to A. sonlaensis , only A. minutiflora and A. urceolata were known at the time of the revision by Li et al. (2000); both species were attributed by them to the section Trilineares G.Z.Li in Li et al. (2000: 211) because both have trimerous flowers.

Figures

FIGURE 1. Aspidistra sonlaensis. A. Habit. B. Rhizome, showing petioles of two foliage leaves and scars of the others. C. Shoot system. D. Inflorescence. E. Flower bud, top view. F. Fruit, side view. G. Fruit, cross section. Trinh Ngoc Bon et al. SCU 2020-01 (type). Photos by N.B. Trinh, correction and design by M. Nuraliev.

FIGURE 2. Aspidistra sonlaensis, floral morphology. A–C. Flower, side, oblique and top views. D. Flower with reddish perigone, top view. E, F. Flower with longitudinally dissected perigone. G. Flower with distal half of perigone removed, top view. H. Perigone base, showing stamens, top view. I. Pistil, view from below. Trinh Ngoc Bon et al. SCU 2020-01 (type). Photos by N.B. Trinh, correction and design by M. Nuraliev.

FIGURE 3. Map of northern Vietnam showing distribution of Aspidistra sonlaensis. Design by M. Nuraliev.