Argyreia argentea (Roxb.) Sweet, Hort. Brit.

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

2. Argyreia argentea (Roxb.) Sweet, Hort. Brit. (ed.) 2: 373. 1830. Lettsomia argentea Roxb., Fl. Ind.

2: 79. 1824. nom. nud. Argyreia argentea (Roxb.)

Choisy, Convolv. Orient. 418: 1834. nom. superfl.

Lectotype (designated here): INDIA, West Bengal, Calcutta , Roxburgh sub., s.d., Wallich Cat. 1364.2

(G-DC [G00134648!]; Isolecto G-DC [G00134902!,

G00134647!, G00134649 digital images!], K

[K000830589 digital image!]). Fig. 1 e-h

A climber 6–7 ft high, sometimes trails in grasslands; stem green, terete, white shiny appressed hairy, older stem not silky hairy, semiwoody. Leaf lamina widely ovate, 8–16 × 7–14 cm, apex acute, base cordate, lobes round, secondary veins 10–13 pairs raised prominently below, upper surface strigulose, lower surface silvery hairy; petiole 8–14 cm long, green, terete, silvery tomentose, shallowly grooved. Inflorescence axillary, 3–7-flowered cyme; peduncle 7–16 cm long, green, terete, hairy like stem. Bracts 2, lanceolate, 1.5–2.5 cm long, persistent, green, hairy like leaf, silvery shiny hairy outer. Sepals 5, sub-equal, outer two narrower, longer while inner three broad and short, outer two 1.5–1.7 cm long, inner three 1–1.2 cm long, lance-ovate in shape, apex shortly acuminate elongates in fruiting, silvery tomentose outer except on overlapped areas, apex acute. Corolla infundibuliform, 5–6 cm long, same across, pink-purple in color, throat c. 1 cm wide, dark purple, hairy on midpetaline bands. Stamens 5, unequal, 3 short, 2 long, longer 2–2.5 cm long while shorter 1–1.5 cm long; filaments white, glandular hairy, dilated at base; anthers c. 4 mm long. Ovary conical; style 2.5–3 mm long; stigma biglobose, white. Berries yellow, fleshy, 1–1.5 cm across.

Flowering & fruiting: Flowering from August to October and fruiting from November to January. Habitat: It climbs on trees along stream and spreads in grasslands. It is one of the early flowering species from North East India.

Distribution & ecology: India (Arunachal Pradesh, Assam, Meghalaya, Mizoram, Nagaland and Tripura), Bangladesh, Thailand and Myanmar.

Etymology: It referes to silvery hairs on the plant body.

Specimens examined: INDIA, Arunachal Pradesh, Namdapha, Deuan Forest area , 3006 ft. 18.12.1993 ,

A. S. Chouhan 99403, 58730 (ASSAM). Assam, Barnadi WLS, Bagawati , 190 m, 20.09.2010 , S.R.

Talukdar 119080, 85378 (ASSAM); Barnadi WLS,

Ralkhara, 137-139 m, 8.09.2011, S. R. Talukdar

122955, 85378 (ASSAM); Khasi and Jaintia

Hills, Mawrynkneng, 21.01.1957, G. Panigrahi

5235, 15552 (ASSAM); Sibsagar , Assam trunk road, 145-146 ft., 29.08.1938, G. K. Deka 18032 ,

19942 (ASSAM). Meghalya, Khasi and Jaiantia hills, 27.08.1935, Sri Sarma 19930 (ASSAM) ;

Cherrapunjee, Near Mawsmai Caves, 06.10.2018,

P.R. Lawand 003 (SUK). Nagaland, Naga Hills , June 1985 , N. L. Bor 21165, 19935 (ASSAM) .

Tripura, Agartala , 30.10.1914, P. M . Debbarman 103 ( CAL) .

Notes: The species was originally described as Lettsomia argentea by Roxburgh (1824). Later, it was transferred to Argyreia by Sweet (1830) and subsequently by Choisy (1833). Most Indian floras attribute the combination ‘ Argyreia argentea ’ to Choisy. However, Sweet’s combination predates that of Choisy, so the correct authority for the name should be A. argentea (Roxb.) Sweet. The combination proposed by Choisy (1834) is therefore an isonym.

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.