Aspidistra pangtiensis D.K. Roy, Y. Mahesh, N. Odyuo & N. Tanaka, 2025

Roy, Dilip Kr., Mahesh, Yalatoor, Odyuo, Nripemo & Tanaka, Noriyuki, 2025, Aspidistra pangtiensis (Asparagaceae), a new species from north-eastern India, Phytotaxa 700 (3), pp. 288-294 : 289-292

Aspidistra pangtiensis D.K. Roy, Y. Mahesh, N. Odyuo & N. Tanaka , sp. nov. ( Fig. 1 , 2 )

Diagnosis: —The new species is morphologically similar to A. elatior , but differs mainly by the leathery (vs. papery) leaf blades, parted (vs. cleft) perianth, subglobose (vs. discoid or hemispheric) stigma white (vs. usually dark purple) in frontal grooves and with a limb more strongly down-curved from the base (vs. distally down-curved), stamens inserted almost on the base (vs. 1.5–4 mm above the base) of the perianth tube, and in the flowering period (summer vs. spring or spring and autumn).

Type: — INDIA. Nagaland: Wokha District, Pangti, transplanted to the Garden of Botanical Survey of India (Eastern Regional Centre, Meghalaya, East Khasi Hills, Shillong, Woodland Campus), 19 September 2024, N. Odyuo 144478 (ASSAM!).

Etymology: —The specific epithet ‘ pangtiensis ’ is derived from the name of the type locality.

Description:—Plant herbaceous, terrestrial, rhizomatous, evergreen, perennial. Rhizome creeping, subterete, 1–1.5 cm thick, covered with scales, nodes dense. Roots fibrous, stout, 1.5–3 mm in diam. Cataphylls on the apical part of rhizome several, varying in size, up to 15 cm long, enveloping base of petiole, becoming black brown when dry, fugacious. Leaves appearing individually with intervals 2.5–3.5 cm, mostly distinctly differentiated into petiole and blade; petiole terete, strait, stiff, adaxially canaliculated, 15–27 cm long, 3–5 mm wide; blade oblong-oblanceolate, 30– 45 cm long, 7–9 cm wide, base attenuate, margin entire, apex acuminate or acute, thick-leathery, lateral main parallel veins impressed adaxially. Peduncle hypogeous, decumbent or ascending, terete, 1.5–2 cm long, topped with erect or obliquely erect flower. Bracts 4–5, white, 0.5–1 cm long, membranous. Flowers solitary on top of the peduncle, positioned at ground level often with the tubular part buried in soil or litter, ca. 2 cm in diam. Perianth campanulate, distally parted into 7–8 lobes (segments), externally dull yellow with purple spots scattered mainly over the lobes; tube subcrateriform, 6–7 mm high, 1.2 cm in diam. in middle, adaxially dark purple distally; lobes subequal, slightly imbricate between the inner and outer ones, inner lobes involute laterally, triangular-lanceolate to ovate, 0.8–1.3 cm long, 0.4–0.6 cm wide, internal medial part with (1–)2 longitudinal close low ribs slightly dilated below and submedial (or submarginal) part with 2 prominent lamellar fleshy keels, distally greenish or yellowish-white, proximally purple adaxially. Stamens 8, inserted almost on the base of the perianth tube; anthers dorsifixed, introrse, ovate, 1.5–2 mm long. Pistil 1, 4-carpellate, shortly umbraculate, not overtopping perianth tube, 8-9 mm high; ovary superior, inconspicuous; style subterete, 2–3 mm long including ovary part; stigma subglobose, smooth, 0.8–1 cm in diam., with centrifugal and centripetal ridges, white in hollows, purple in ridges and margins on frontal side, limb sharply descending (or strongly curved downward) from the base, rear side white. Fruit not seen.

Ecology and phenology:— The new species was collected as a cultivated plant in a forest village, hence its natural habitat is not known. However, the village is situated in a mixed evergreen hilly forest. Some of the predominant species of the forest to be mentioned are Bischofia javanica , Alangium chinense , Parkia timoriana , Archidendron clypearia , Ficus auriculata , F. cyrtophylla , Croton joufra , Phlogacanthus tubiflorus , Phrynium pubinerve , Zingiber zerumbet , Rhynchotechum ellipticum , etc. Flowers in August–September.

Conservation status:— Due to the lack of adequate information on the distribution and/or population status, the new species here is categorized as Data Deficient (DD) ( IUCN 2024).

Distribution: —The new species is known only from the type locality in Pangti Village under Wokha District in the state of Nagaland, India.

Taxonomic relationships: — Aspidistra pangtiensis is closely similar to A. elatior in various traits of floral and vegetative parts. For example, they share solitary (not tufted) foliage leaves of which the main longitudinal parallel veins are (slightly) impressed on the adaxial side, and perianth lobes slightly imbricate between the inner and the outer ones. A. pangtiensis differs, however, by the thick-leathery (vs. thick-papery) leaf blades, perianth segments parted a little more than ca. 2/3 (vs. cleft ca. 1/2) of the entire perianth length on the external side, subglobose (vs. discoid or hemispheric) stigma white (vs. usually dark purple) in frontal hollows and with a limb sharply descending (or more strongly down-curved) from the base (vs. down-curved distally), stamens inserted almost on the base (vs. 1.5–4 mm above the base) of the perianth tube, and in the flowering period (summer vs. spring or spring and autumn). A. elatior comprises two subspecies; subsp. elatior and subsp. cephalostigma Tanaka (2016: 32) . In having a subglobose stigma, the new species looks more similar to subsp. cephalostigma which has a hemispheric stigma. But, this does not indicate that they are phylogenetically closer. The resemblance in their stigmas is apparently homoplastic, as the two species differ significantly not only in several morphological traits stated above but also in geographical range. A detailed comparison of A. pangtiensis with A. elatior is presented in Table 1.

As aforementioned, A. pangtiensis was collected by a local resident in a nearby forest of a remote village in Nagaland, NE India. On the other hand, wild plants identifiable as A. elatior have not been recorded from India. Further, in our knowledge A. elatior is not cultivated in NE India or in mainland India. Aspidistra pangtiensis is hence considered to be a native species in India. It is particularly of interest and noteworthy that two such closely similar species, A. pangtiensis and A. elatior , occur disjunctively in far distant regions, NE India and E Asia ( Japan, Korea), which necessitates further study on their relationships in the future.

In northern Thailand and southwestern China (Yunnan), there is A. sutepensis ( Phonsena & de Wilde 2010, Ding et al. 2021) which is also somewhat similar in traits of flowers and vegetative parts to both A. pangtiensis and A. elatior subsp. elatior . In particular, it is noteworthy that A. pangtiensis and A. sutepensis share a stigma white in the hollows and purple in the ridges and margins on the frontal surface. This is in marked contrast with the stigma of A. elatior which is usually dark purple including hollows. It also seems significant that A. pangtiensis and A. sutepensis share inner perianth lobes involute laterally. A. pangtiensis is, however, readily distinguishable from A. sutepensis chiefly in its thicker rhizome (10–15 vs. 3–10 mm in diameter), foliage leaves usually more closely set (vs. widely spaced) on the rhizome, leathery (vs. papery) leaf blades with adaxially impressed (vs. non-impressed) longitudinal veins, perianth parted a little more than ca. 2/3 (vs. cleft up to ca. 1/2) of the entire length on the external side, stamens inserted almost on the base (vs. at the lower 1/3 part) of the perianth tube, subglobose (vs. peltate) stigma, and in the flowering period (August–September vs. October–December) (data of A. sutepensis mainly excerpted from Phonsena & de Wilde 2010 and Ding et al. 2021). Because of these differences, we consider A. pangtiensis to be a distinct species. A. pangtiensis occurs closer in geographical distribution to A. sutepensis than to A. elatior . This may indicate that A. pangtiensis is more closely related to A. sutepensis than to A. elatior .

To elucidate phylogenetic relationships between A. pangtiensis and other similar species such as A. sutepensis , A. elatior and A. fimbriata F.T.Wang & K.Y.Lang in Lang (1978: 76), it is desirable to further conduct multidisciplinary analyses, including molecular and chromosomal ones.

Figures

FIGURE 1. Aspidistra pangtiensis. A & B. Habit. C. Rhizome, with inflorescence and basal part of leaves. D. Plant, with flower.

FIGURE 2. Aspidistra pangtiensis. A. Flower, frontal view. B. Flower, lateral view. C. Longitudinal section of flower. D. Perianth, side view. E. Perianth lobes detached. F. Pistil, lateral view. G. Pistil, view from below. H. Stamens, seen from above.