Aspidistra phongdiensis D.Dien, T.A.Le & Vislobokov, 2023

Chinh, Vu Tien, Dinh, Dien, Le, Tuan Anh, Doan, Quoc Tuan, Le, Ngoc Tuan, Le, Van Huong, Tran, Nam Thang & Vislobokov, Nikolay A., 2023, Aspidistra phongdiensis (Asparagaceae), a new species from Central Vietnam, Phytotaxa 591 (1), pp. 64-70 : 65-67

Aspidistra phongdiensis D.Dien, T.A.Le & Vislobokov , sp. nov. ( Fig. 1 )

Diagnosis: Aspidistra phongdiensis is morphologically similar to A. khangii but differs in wider leaf blade (vs. narrowly elliptic), perigone white outside (vs. purple mottled), yellow pollen (vs. white), introrse anthers (vs. latrorse) and widely obconic pistil (vs. deskshaped).

Type: — VIETNAM. Thua Thien Hue province : Phong Dien district , Phong Xuan commune, Phong Dien Nature Reserve, 16°24′14.73″N, 107°13′27.59″E, 350 m a.s.l., 18 April 2021, Dien Dinh, Quoc Tuan Doan, Vu Tien Chinh, Le Ngoc Tuan, Le Van Huong, Tran Nam Thang, Tuan Anh Le LTA 2337 (holotype VNMN!; isotype SGN!) .

Plant perennial, evergreen, herbaceous, rhizomatous, glabrous. Rhizome creeping, epigeous, 0.6–1 cm in diameter, distal part (3–4 cm) ascending to vertical with prop roots. Roots grey, 2.5–4 mm in diameter. Rhizomes with regularly repeating units, each comprising a few distichously arranged phyllomes (cataphylls followed by a foliage leaf). Cataphylls oblong, 9–15 cm long, 1–1.3 cm wide, rapidly withering. Foliage leaves green, divided into petiole and lamina. Petiole green, adaxially sulcate, 20.6–27 cm long, 5–8 mm in diameter. Lamina green, elliptic, basally cuneate, apically narrowly acuminate, 28–30 cm long, 8.5–10.5 cm wide, parallel-veined with median vein prominent on abaxial surface, margin entire. Peduncle (specialized reproductive shoot) arising horizontally and arching down, purple mottled, 2.8–13 cm long, 3–4 mm in diameter, with 5–6 dark green and purple mottled, broadly ovate, 7–9 mm long, 5–11 mm wide distichously arranged sterile bracts. Flower solitary at the top of the peduncle. Perigone broadly obovate, globoid, container-shaped (urceolate with inflexed lobes), down faced, white outside, purple-red inside, fleshy, ca. 3 mm thick; tube widely campanulate, 2.7–3 cm long, 3.6–5 cm in diameter; lobes 6, widely ovate to triangular, incurved forming a star-like perigone opening, 2.4–2.9 mm in diameter. Stamens 6, inserted at base of perigone tube at the same radii with perigone lobes; anthers subsessile, yellow, ovoid, 2 mm long, 1.3–1.5 mm wide, introrse. Pistil uniformly white, widely obconic to club-shaped, 9–10 mm long; ovary superior, inconspicuous, 3-locular; style widely obconic, roundish hexagonal in cross section, with 12–13 longitudinal ridges, up to 10 mm long, 4 mm in diameter at base; stigma disk-shaped, fleshy, 14–15 mm in diameter, upper surface tuberose with 3 radial bifurcated grooves, hexagonal, side surface with 20 prominent longitudinal ridges. Fruits dull green to brow, subspherical, 1.6–2.5 mm in diameter, with conical protuberances 1–2.5 mm long.

Paratype: — VIETNAM. Thua Thien Hue province : Phong Dien district , Phong Xuan commune, Phong Dien Nature Reserve, 16°24′14.73″N, 107°13′27.59″E, 350 m a.s.l., 11 March 2023, Dien Dinh, Quoc Tuan Doan, Vu Tien Chinh, Le Ngoc Tuan, Le Van Huong, Tran Nam Thang, Tuan Anh Le LTA s.n. ( VNMN!, SGN!, MW!) .

Etymology: —The specific epithet is derived from its type locality, in Phong Dien Nature Reserve, located in Phong Dien district, Thua Thien Hue province, central Vietnam.

Vernacular name: —Tỏi đá phong điễn.

Phenology: —Flowering from March to April, and fruiting from April to May in natural habitat.

Distribution and ecology: — Aspidistra phongdiensis is only known from type locality where it is common ( Fig. 2 ). The new species grows in primary and secondary evergreen broad-leaved lowland forest on alluvial soils at elevation around 850 m a.s.l., commonly on shady reclined slopes in assemblage with Piper sp. , Calamus tetradactylus Hance (1875: 289) , Blastus cochinchinensis Loureiro (1790: 527) , etc.

Conservation status: —Although the new species is located in a protected area, it grows near to the landslide area. Thus, following the IUCN Red List Categories and Criteria (IUCN 2021), it is provisionally assessed as Data Deficient (DD).

Taxonomic relationships: —The new species is morphologically closest to A. khangii by shape of perigone but differs in shape of leaf blade (elliptic 8.5–10.5 cm wide vs. narrowly elliptic 2–7 cm wide), colour of perigone (white outside vs. purple mottled outside), colour of pollen (yellow vs. white), type of anther dehiscence (introrse vs. latrorse) and shape of pistil (widely obconic vs. desk-shaped) ( Averyanov & Tillich 2014, Averyanov et al. 2019b).

In flower structure A. phongdiensis is also similar to A. locii but differs in colour of perigone (white outside, purple-red inside vs. uniformly grass green), presence of six perigone lobes (vs. absence of free lobes), number of stamens (6 vs. 12–21), type of anther dehiscence (introrse vs. latrorse) and shape of pistil (widely obconic vs. deskshaped) ( Bogner & Arnautov 2004, Averyanov et al. 2019b).

In flower coloration the new species is similar to A. austroyunnanensis Hu, Cai & Wang in Cai et al. (2018: 233), but differs in perigone lobes orientation (curved inward vs. curved outward), stamens morphology (subsessile anthers vs. with filaments 2–3 mm long) and shape of pistil (widely obconic with longitudinal ridges vs. mushroom-shaped smooth) ( Cai et al. 2018).

Figures

FIGURE 1. Aspidistra phongdiensis. A. Habit, scale bar: 10 cm; B. Flower, apical view; C. Sterile bracts of peduncle, scale bar: 1 cm; D. Flower, lateral view, scale bar: 5 cm; E. Perigone, dissected to show stamens and pistil, scale bar: 2 cm; F. Pistil, scale bar: 5 mm; G. Stamens, scale bar: 2 mm; H. Fruits, scale bars: 2 cm.

FIGURE 2. The known geographical distribution of Aspidistra phongdiensis in Phong Dien Nature Reserve, located in Phong Dien district, Thua Thien Hue province, central Vietnam.