Aspidistra tripartita Vislobokov & Nuraliev, 2024

Vislobokov, Nikolay A., Moshkina, Natalia A., Kuznetsova, Svetlana P., Kuznetsov, Andrey N., Le, Son Xuan, Romanov, Mikhail S., Drokina, Victoria G., Lyskov, Dmitry F., Kopylov-Guskov, Yury O. & Nuraliev, Maxim S., 2024, Aspidistra tripartita (Asparagaceae, Convallarioideae), a new species from Vietnam, Phytotaxa 666 (1), pp. 42-50 : 43-47

Aspidistra tripartita Vislobokov & Nuraliev , sp. nov. ( Fig. 1–3 )

Diagnosis: — Aspidistra tripartita belongs to a group of species characterized by campanulate to cupulate perianth tube and deeply lobed stigma. It differs from all the other species of the group by thick rhizome (more than 10.5 mm in diameter), long and narrow leaf blades (28–71.5 cm long and 2.6–3.1 cm wide), and stamens with supraconnectives. Within this group, the new species is morphologically most similar to A. wujiangensis , being additionally distinct from the latter by shorter petiole (up to 12.5 cm long), flower with 6 tepals and 6 stamens, and crimson perianth lobes.

Type: — VIETNAM. Son La province: Bac Yen district, Ta Xua Nature Reserve, disturbed forest on slope, 21°18’50’’N 104°31’55’’E, elev. 1350 m, collected in nature on 6 October 2019, Nuraliev M. S., Kopylov-Guskov Yu. O., Lyskov D. F. 2839, the herbarium specimen prepared from the living cultivated plant (garden number: 2019.15552) on 27 April 2023, Moshkina N. A. and Stepanov S. V. s.n. (holotype MW 0595858!).

Additional specimen examined (paratype): — VIETNAM. Son La province: Phu Yen district, vicinity of Ta Xua Nature Reserve, forest with bamboo on local ridge, 21°21’38’’N 104°39’55’’E, elev. 780 m, collected in nature on 8 October 2019, Nuraliev M. S., Kopylov-Guskov Yu. O., Lyskov D. F. 2870, the herbarium specimen prepared from the living cultivated plant (garden number: 2019.15551) on 31 August 2024, Romanov M. S. s.n. ( MW 0595859!).

Specimens in living collections: —Living plant from the same gathering as the type (Nuraliev et al. 2839), garden number: 2019.15552; living plant from the same gathering as the paratype (Nuraliev et al. 2870), garden number: 2019.15551.

Etymology: —The specific epithet refers to the stigma deeply divided into three narrow lobes, which readily distinguishes the new species from most of its congeners.

Description:—Plant perennial, herbaceous, evergreen, rhizomatous, glabrous (except for having root hairs). Rhizome creeping, branching, hypogeous (to epigeous), ascending to vertical in distal part, dark green when young, brown when mature, with very short internodes, 10.8–16.3 [13.2] mm in diameter. Rhizome with regularly repeating units, each unit comprising distichously arranged phyllomes: several cataphylls followed by a single foliage leaf. Roots brownish white, 1.2–1.9 [1.5] mm in diameter, spreading from rhizome almost horizontally. Cataphylls light green, lanceolate, acuminate at apex, 6.8–13 [9.2] cm long, 5.4–7.9 [6.5] mm wide, rapidly withering. Leaves distinctly divided into petiole and blade. Petiole green, stout, straight, more or less vertical, adaxially sulcate, 4–12.5 [8.8] cm long, 3.5–4.9 [4.2] mm wide, distally with gradual transition to blade. Leaf blade green, ensiform to very narrowly elliptic, attenuate at base, gradually tapering to acuminate apex, 28–71.5 [49.1] cm long, 2.6–3.1 [2.8] cm wide, parallel-veined with median vein prominent on abaxial surface, margin entire. Inflorescences axillary, solitary. Peduncle spreading more or less horizontally, mostly underground, greenish with crimson speckles, ca. 7.4 mm long, 2 mm in diameter, with 3 sterile bracts (2 of them placed directly at flower base and appressed to perianth tube). Sterile bracts scaly, pale red mottled with crimson, translucent, ca. 4.3 mm long, ca. 4.1 mm wide. Flower solitary at top of peduncle. Perianth almost uniformly crimson (usually with greenish tips of tepal lobes), fleshy, 11.6–12.2 [12] mm long, 11.8–15.2 [12.8] mm in diameter, outside smooth and inside more or less prominently verrucose; tube cupulate to nearly campanulate, 6–6.9 [6.6] mm long, 10.1–10.4 [10.3] mm in diameter; lobes 6(–7), apparently in two whorls due to overlapping bases, erect to slightly spreading, triangular, 3.8–5.1 [4.5] mm long, 5.1–5.8 [5.5] mm wide at base, obtuse to rounded at apex, each lobe adaxially with 2–4 prominent keels ca. 0.4 mm high. Stamens 6(–7), inserted at middle of perianth tube in the same radii with tepals, oriented horizontally to slightly ascending (almost perpendicular to the wall of perianth tube, apically pointing the flower center and with anthers facing the base of perianth tube), crimson except for white to light yellow thecae, 2.9–4.2 [3.5] mm long, prominently verrucose throughout; filaments 0.8–1.5 [1] mm long; anthers 1.4–1.9 [1.6] mm long, 0.9–1.1 [1] mm wide, introrse, with ovate thecae and prominent supraconnectives; supraconnectives subulate, apically touching the style and recurved toward abaxial (rarely adaxial) side, 0.6–1.4 [1] mm long. Pistil crimson, mushroom-shaped or table-shaped (to umbrella-shaped), ca. 3.9 mm high. Ovary superior, inconspicuous. Style cylindrical, terete to slightly longitudinally ridged, ca. 2.5 mm long, 1.9 mm in diameter at base. Stigma obconoid in outline, ca. 1.5 mm high, 4.8–7.5 [6.2] mm in diameter, with verrucose upper surface, deeply divided into 3(–4) narrow radial lobes; each lobe cylindrical, at apex widening and shortly bifurcate, apices sometimes curved downwards. Fruit unknown.

Distribution and ecology: — Aspidistra tripartita is currently known to be endemic to Ta Xua Nature Reserve and its vicinities, where it was recorded in two localities. Although these localities are close to each other, with about 15 km (air distance) between them, they differ considerably in elevation (780 m and 1350 m) and, accordingly, in temperature regime.

Taxonomic relationships: — Aspidistra tripartita belongs to a group of species characterized by campanulate to cupulate perianth tube and deeply lobed stigma. The other species of this group are the Chinese endemics A. cruciformis Y.Wan & Xiao H.Lu in Wan & Huang (1987: 217), A. huanjiangensis Li & Wei (2003: 384) , A. quadripartita Li & Tang (2002: 289) (including A. columellaris Tillich in Tillich & Averyanov (2012: 204)) and A. wujiangensis W.F.Xu & S.Z.He in Xu et al. (2015: 297). A comparison of these five species is presented in Table 1.

Aspidistra tripartita is unique among the species of this morphological group in several traits. First, it possesses a thick rhizome (10.8–16.3 mm in diameter), which is comparable only to that of A. cruciformis (6–12 mm in diameter). Then, the new species has long and narrow leaf blades: they are 28–71.5 cm long and 2.6–3.1 cm wide, whereas in the other four species the blades are not longer than 36 cm and, except for A. huanjiangensis , at least 3.2 cm wide. These dimensional differences also lead to unusual shape of leaf blade of the new species, which is ensiform or nearly so. Finally, A. tripartita strikingly differs from the other species in the presence of supraconnectives.

In addition, A. tripartita is distinct from A. cruciformis in shorter petiole (4–12.5 vs 30–50 cm long), gradual (vs abrupt) transition between petiole and leaf blade, flower merism (6 vs 8 tepals and stamens), and smaller stigma (4.8–7.5 vs 12–14 mm in diameter).

The new species differs from A. huanjiangensis in wider petiole (3.5–4.9 vs 1.5 mm wide), gradual (vs abrupt) transition between petiole and leaf blade, and coloration of outer perianth surface (crimson vs greenish yellow or reddish).

Aspidistra tripartita differs from A. quadripartita in shorter petiole (4–12.5 vs 20–35 cm long), gradual (vs abrupt) transition between petiole and leaf blade, flower merism (6 vs 8 tepals and stamens), and coloration of outer perianth surface (crimson vs yellowish green or green to beige).

The new species differs from A. wujiangensis in shorter petiole (4–12.5 vs 14–26 cm long), flower merism (6 vs 8 tepals and stamens), and coloration of perianth lobes (crimson vs yellowish white).

Figures

FIGURE 1. Aspidistra tripartita, type gathering. A. Habit. B. Inflorescence. C, D. Flower, half-side and top view. E. Flower, side view. F. Longitudinal half of perianth with stamens, view from inside. G. Flower, longitudinal section. Photos:A by M.S. Nuraliev from nature (Nuraliev et al. 2839); B‒G by M.S. Romanov from cultivated plant (2019.15552).

FIGURE 2. Aspidistra tripartita, type gathering. A. Flower, top view. B. Flower, longitudinal section. C, D. Detached stamens. E, F. Stigma with style, top view and view from below. Photos by M.S. Romanov from cultivated plant (2019.15552).

FIGURE 3. Aspidistra tripartita, paratype. A. Habit. B. Flower, half-side view. C. Flower, longitudinal section. D, E. Stigma with style, top view and view from below. Photos: A by M.S. Nuraliev from nature (Nuraliev et al. 2870); B‒E by M.S. Romanov from cultivated plant (2019.15551).