Aeschynanthus chayangtajoensis Chowlu, A.Shenoy & A.Ray, 2024

Chowlu, Krishna, Shenoy, Akshath, Ray, Ajit & Kabeer, Althaf Ahamed, 2024, Aeschynanthus chayangtajoensis (Gesneriaceae), a new species from Arunachal Pradesh, India, Phytotaxa 678 (1), pp. 65-70 : 66-67

Aeschynanthus chayangtajoensis Chowlu, A.Shenoy & A.Ray , sp. nov. ( Fig. 1 )

Diagnosis:— Aeschynanthus chayangtajoensis resembles A. acuminatus , A. moningerae and A. pedunculatus in its habit, obovate or elliptic leaves, papery to slightly fleshy texture, acute or acuminate at apex, and seeds with single hilar appendage and moderately spiral testa cell orientation, but it differs from A. acuminatus by 2–6(–10) cm long peduncle (vs. 0.8–4.5 cm long), ovate bract (vs. orbicular), non-reflexed, 7–10 mm long calyx lobe (vs. reflexed, 2.5–5(–7) mm long), gibbous corolla base (vs. non-gibbous), ca. 1 mm long staminodes (vs. 0.13–15 mm long), glabrous gynoecium (vs. pubescent), 8–12 cm long capsule (vs. 10.5–22 cm long), and papillose seed grain (vs. warty). It differs from A. moningerae by 7–10 mm long calyx lobe (vs. 3–5 mm long), 1.7–2.3 cm long corolla (vs. 2.8–3 cm), gibbous corolla base (vs. non-gibbous), glabrous gynoecium (vs. pubescent) and 8–12 cm long capsule (vs. 12–29 cm long), and papillose seed grain (vs. fairly smooth to warty). It differs from A. pedunculatus by 2–6(–10) cm long rigid peduncle (vs. 2.8–23 cm long; delicate) and ovate or elliptic, non reflexed calyx lobes (vs. narrowly elliptic, erect or slightly spreading), acute or round calyx lobes (vs. acuminate to acute, more rarely obtuse), 1.7–2.3 cm long corolla (vs. 2.9–3.7 cm long), gibbous corolla base (vs. non-gibbous), 1.8–2.7 cm long filament (vs. 2.9–3.6 cm), glabrous gynoecium (vs. pubescent), and 8–12 cm long capsule (vs. 17–27 cm long).

Type: — INDIA. Arunachal Pradesh: East Kameng district, near Chayangtajo, 27°42´43.78´´N, 93°10´38.41´´E, elev.ca. 1300m a.s.l., 16September2024, K.Chowlu A.Shenoy &A.Ray 49342 (holotypeARUN codeARUN000038030!, isotypes: ARUN, CAL)

Description: —Epiphytic perennial undershrub with hanging stems. Stems robust, terete, green, grey-brown at mature, glabrous; nodes swollen; internodes 3.2–8 cm long. Leaves opposite; petioles 2–5 mm long, terete, glabrous; leaf blade 4.2–7.2 × 1.4–3.2 cm, obovate or elliptic, papery to slightly fleshy, base rounded, margins entire, apex acute or acuminate, green above, pale green below, midvein prominent, lateral veins 6–8, obscure or clearly visible, tertiary venation obscure, glabrous. Inflorescence axillary, pseudoterminal, 1–8-flowered; peduncles 2–6 cm long; bracts 8–10 mm long, ovate, round to acute at apex, margins entire, green, mid vein prominent, glabrous, persistent; pedicels 1–1.5 cm long, greenish-brown, glabrous; bracteole 6–8 mm long, ovate to lanceolate, apex acute, margins entire, green, mid vein prominent, glabrous, persistent. Calyx lobes nearly free to base, 0.7–1 cm long, ovate or elliptic, not recurved, apex acute or rounded, margins entire, pale green at base, brownish towards apex, glabrous, persistent. Corolla tubular, 1.7–2.3 cm long, gibbous at base, gradually expanding towards the mouth, ca. 6 mm wide at base, 8– 1.2 mm wide at mouth, scarlet, glabrous outside, densely glandular pubescent only at the mouth and lobes, limb indistinctly 2-lipped; upper lobes erect, 3.4–5.1 × 2.4–4.6 mm, round at apex; lateral lobes spreading or reflexed, 3.8–5.6 × 3.1–5.1 mm, ovate-elliptic; lower lobes spreading, 3.6–5.3 × 3.1–5.2 mm, ovate-elliptic. Stamens 4, coherent in 2 pairs; filaments short, exerted; uniformly dark red to maroon, sparsely pubescent; anterior filaments 2.1–2.7 cm long, inserted at 0.6 cm from corolla base; posterior filaments ca. 1.8 cm long, inserted at 1.1 cm from corolla base; anthers 2 mm long, yellow to brown; staminode ca. 1 mm long, clavate, light yellow. Disk ca. 3 × 3 mm, cylindrical, shallowly crenate, yellow, glabrous. Pistil 2.2–2.8 cm long; stipe ca. 0.6 cm long, glabrous; ovary 1.2–1.6 cm long, pale green, with glandular hairs; style ca. 0.4 cm long, glabrous; stigma capitate, ca. 1 mm across, yellowish. Capsules 8–12 cm long, pale green with brown shade, erect to slightly curved; seeds 0.35–0.48 × 0.025 mm, elongated; testa cells papillose, bubble cells absent, slight to moderate clockwise orientation; apical appendage a filiform hair, 2mm long; hilar appendage a solitary filiform hair, 1.5 mm long, appendages not papillose.

Etymology: —The specific epithet refers to the locality in Arunachal Pradesh, where the species was discovered. Chayang Tajo is one of the oldest and remote villages in the Indian state of Arunachal Pradesh, selected under Vibrant Village Programme, a Government of India sponsored scheme aiding to identify and develop the economic drivers based on local, natural, human and other resources of the border villages on the northern border of India.

Distribution and habitat: —The new species is only known from the type locality, at an elevation of 1300 m a.s.l. It grows as epiphyte on Ficus Linnaeus (1753: 1059) spp. , and Knema Loureiro (1790: 604) spp. in the evergreen forests.

Phenology: —Flowering from July to September and fruiting from August to October.

Conservation status and preliminary IUCN assessment: —Currently, the new species is known only from one single site in the type locality. According to the nearby field investigations, it is found that, the new species has a very restricted almost punctiform distribution and known population is represented by a limited number of individuals. The area of occupancy (AOO) and the Extent of occurrence (EOO) are both of 04 km². The growing sites of this plant is a remote area with limited access to humans, but are currently threatened by forest fire and collection of firewood by local people, which could lead to a significant decrease of the populations in the area since the plant is an epiphyte. Therefore, following the IUCN (2022, 2024), the new species is here assessed as Critically Endangered (CR) under criterion B, B1ab(iii)+2ab(iii).

Taxonomic notes: —The seeds of Aeschynanthus chayangtajoensis have a smooth filiform appendage at each end, without bubble cells; the testa cell orientation is moderately spiral and the papillae formed from single cells ( Fig. 1q ). According to Mendum et al. (2000), the new taxon belongs to the section Haplotrichium Benthem (1976: 1014) .

Figures

FIGURE 1. Aeschynanthus chayangtajoensis. A–C. Habit, D. Flower, front view, E. Flower, Side view, F–G. Leaf, adaxial and abaxial surfaces, H–I. Calyx, views from outside and from inside, J. Bracts, K. Bracteoles, L–M. Corolla artificially opened, view from inside, N. Staminode, O. Capsule, P–Q. Seed, R. Pistil. [Photos by K. Chowlu, A. Shenoy & A. Ray]