Argyreia arakuensis N.P.Balakr., Bull. Bot. Surv.

P. R., Lawand & Shimpale, V. B., 2024, Revision of the genus Argyreia (Convolvulaceae) from India, Rheedea 34 (5), pp. 337-396 : 342-344

1. Argyreia arakuensis N.P.Balakr., Bull. Bot. Surv. India 3: 163. 1962. Type: INDIA, Andhra Pradesh, Araku valley, 14.09.1961, N.P. Balakrishnan 540A (holo CAL [ CAL0000018491 !); iso K [ K001081758 digital image!]). Fig. 1a–d

A climber, up to 6–7 ft. height; stems purplish green,white sericeous, older glabrous, semiwoody.

Leaf petiole white sericeous, 8–17 cm long,

shallowly grooved above, terete; leaf lamina widely ovate, 14–18 × 12–15 cm, base cordate, shallowly cordate or sometimes rounded, apex acute or mucronate, white hairy above, densely white tomentose on lower surface, tomentum not shiny,

secondary veins 8–9 pairs, raised on lower surface. Inflorescence an axillary 10–15-flowered compact cyme; peduncle 8–12 cm long, usually equaling or shorter than the petiole, white tomentose. Bracts 1–3, outer bracts 3–4 cm long, leafy, petiolate, hairy like leaf, flower bracts linear lanceolate, 2–3 cm long, white strigose outer, strigulose inside, broad at apex, apex acute. Flowers pedicellate; pedicel c. 5 mm long. Sepals 5, subequal, 2–2.3 cm long, lance-ovate, apex acuminate, hairy outer except on overlapped hyaline margins, sepals enlarge in fruit. Corolla 6–7 cm long, up to 6 cm across, pink-purple, throat dark purple, corolla hairy outer on midpetaline bands. Stamens 5, 3 short- 1–1.2 cm long, 2 long- 2–2.2 cm long; anthers 4 mm long, white; filament dilated and glandular hairy at base. Ovary pale white; style white; stigma biglobose, white. Berries yellow, fleshy, 1 cm across.

Flowering & fruiting: Flowering from August to October and fruiting from November to January.

Habitat: It thrives at altitudes of 800 meters and above, flourishing in cold climates, and is commonly found along hilly roadsides.

Distribution: India (Andhra Pradesh); endemic.

Etymology: The specific epithet is derived from Araku region, a type locality of the species.

Specimens examined: INDIA, Andhra Pradesh, Visakhapatnam District, Araku Valley , 800 m ,

14.09.1961, N. P . Balakrishnan 540, 540A (CAL

[CAL0000018481]); Visakhapatnam District,

Araku Valley, 20,09.2018, P.R. Lawand 001 (NCK);

Visakhapatnam District , Paderu, 21.09.2018, P. R .

Lawand 030 (NCK).

Conservation Status: The species is known from less than 10 locations from the Araku valley tehsil and its area of occupancy (AOO) may not exceed 500 Km 2. So, the species meets the criterion ‘B’ of the IUCN. The species occurs along roadsides or along forest borders, hence the threats posed by developmental strategies can’t be overlooked. It is observed that the number of mature individuals in subpopulations will not exceed 500 individuals. The species qualifies the IUCN (2024) criteria B2a and C2ai, hence we propose the conservation status of Vulnerable (VU).

Notes: Staples and Traiperm (2017) doubted the status of the species, however, characters like white tomentum on abaxial leaf, long pedunclulate compact cyme, linear bracts distinguish the species from its congenerics.

Figures

Fig. 1. Argyreia arakuenSiS N.P. Balakr. (a-d): a. Flowering twig; b. Inflorescence; c. Bracts; d. Sepals. Argyreia argentea (Roxb.) Sweet (e-h): e. Flowering & fruiting twig; f. Leaf abaxial surface; g. Bract; h. Sepals. Argyreia barbigera Choisy (i-l): i. Flowering twig;j. Flower; k. Bracts; l. Sepals.