Aspidistra backanensis C.R. Lin, K.S. Nguyen & W.B. Xu, 2024

Lin, Chun-Rui, Nguyen, Khang Sinh, Qin, Ying, Zou, Chun-Yu, Xu, Wei-Bin & Liu, Yan, 2024, Six new species of Aspidistra (Asparagaceae: Convallarioideae) from China and Vietnam, Phytotaxa 671 (3), pp. 231-246 : 242-244

6. Aspidistra backanensis C.R. Lin, K.S. Nguyen & W.B. Xu , sp. nov. ( Fig. 6 )

Type:— VIETNAM. Bac Kan Province: type herbarium specimen prepared from plant cultivated at Guilin Botanical Garden ( CN), 15 May 2023, Chun-Rui Lin 1759 (holotype: IBK). Living plant was collected from northern Vietnam, Bac Kan Province, Ba Be National Park, at the foot of the mountain, under the evergreen broad-leaved forest on limestone mountain, 22.397°N, 105.635°E, at elevation about ca. 260 m a.s.l., 21 August 2019.

Additional specimen examined (paratype):— VIETNAM. Bac Kan Province: Ba Be National Park, 21 August 2019, Wei-Bin Xu, K. S. Nguyen & Chun-Rui Lin 13971 ( IBK, HN).

Diagnosis:— The new species is morphologically similar to A. superba , but clearly distinguished by its smaller leaf blade broadly ovate to ovate-lanceolate, base rounded or subcordate, shorter petiole 5–9 cm long, stigma upper surface purplish red, the center obviously convex, with 4 trailing hemispherical-lobed prominently, and 4 inconspicuous radial, white lines with 5 forks at apex.

Herbs perennial, evergreen, rhizomatous. Rhizome creeping, subterete, 6–8 mm in diameter, nodes dense. Leaf sheath 4–5, purplish red, 1–7 cm long, enveloping base of petiole, becoming black-brown when dry. Leaves solitary, ca. 1cm apart; petiole stiff upright, 5–9 cm long, ca. 2 mm in diameter, adaxially sulcate; leaf blade usually ovate to ovate-lanceolate, 9–14.5 long and 7–9.5 cm wide, green, apex acuminate, base nearly rounded or subcordate, abruptly narrow into petiole, inequilateral, margin entire, mid vein strongly prominent on abaxial surface, secondary veins 4–5 pairs, abaxially prominent. Peduncle decumbent, purplish red, 1–2.5 cm long, with 4–6 bracts, the two bracts at the base of perianth broadly ovate, white with purplish red spots, ca. 2 cm long, 2–2.5 cm wide, apex acuate or shortly acuminate. Flowers solitary. Perianth urceolate, fleshy, deeply 8 lobed apically; lobes recurved or arcuate, triangular lanceolate, 18–24 mm long and 3–4 mm wide at base, outside whitish with purplish red mottled densely, inside pale yellow and sometimes with purplish-red speckles at base, apex long acuminate, each lobe basally with an adaxial, toothlike appendage, appendages white and frequently spotted with purplish-red, ca. 2× 3 mm, apex 2–3 denticulate, appendages protruding horizontally or obliquely over tube opening similar to an iris diaphragm reducing the opening to 5–6 mm; tube 10–14 mm long, widest part 18–22 mm in diameter, outside white with purplish red spots, inside deep purple to nearly black, with 8 keels from the stamen bases running up to the mouth of perianth tube. Stamens 8, opposite to lobes, inserted at ca. 2 mm from the base of perianth tube, positioned conspicuously lower than stigma; anthers subsessile, subglobose, ca. 1.5 mm long and wide, pollen yellow. Pistil 10–12 mm long, ovary indistinct, style cylindrical, short, 1–2 mm long, 3–4 mm in diameter, stigma disc-shaped, enlarge, 16–20 mm in diameter, upper surface purplish red, the center obviously convex, and with 4 trailing hemispherical-lobed, each lobe distally descends and extends to margin, apex with 4 inconspicuous radial, white lines with 5 forks, margin sinuate and bent upward, lower surface white, with 16 longitudinal ribs.

Phenology:— The new species was observed flowering from April to May.

Etymology:— The specific epithet refers to the type locality, Bac Kan Province, northern Vietnam.

Distribution and ecology:— At present, Aspidistra backanensis is known only from Ba Be National Park, Bac Kan Province, northern Vietnam. It grows under evergreen broad-leaved forest on limestone mountains, at elevation range of 250–300 m, not common.

Similar species:— The new species is similar to Aspidistra superba Tillich (2005: 323) in the floral morphology, but differs by its shorter leaf petiole (5–9 vs. 15–22 cm) long, leaves ovate to ovate-lanceolate (vs. widely lanceolate), smaller leaf blade (9–14.5 vs. 16–18 cm) long, stigma upper surface purplish red (vs. red and white), the center obviously convex (vs. concave), with 4 trailing hemispherical-lobed (vs. heart-shaped) prominently, and 4 inconspicuous radial, white lines with 5 forks at apex (vs. 16 prominent rays ending in 16 teeth). A detailed morphological comparison between the two species is provided in Table 4.

Figures

FIGURE 6. Aspidistra backanensis: (A) plant in nature; (B) flowering plant; (C, D) flowers; (E) perianth dissected to show stamens; (F) flower bottom view; (G) flower longitudinally dissected; (H) bracts; (I) pistil; (J) stigma bottom view; (K) stigma top view; (L) flower with half of perianth removed showing pistil.