Argyreia atropurpurea (Wall.) Raizada, Indian Forester

P. R., Lawand & Shimpale, V. B., 2024, Revision of the genus Argyreia (Convolvulaceae) from India, Rheedea 34 (5), pp. 337-396 : 344-345

3. Argyreia atropurpurea (Wall.) Raizada, Indian Forester 93: 754. 1967. Convolvulus atropurpureus Wall. in Roxb., Fl. Ind. 2: 54.

1824. Ipomoea atropurpurea (Wall.) Sweet, Hort.

Brit. ed. 2: 371. 1830. Lettsomia atropurpurea

(Wall.) C.B.Clarke in Hook.f. Fl. Brit. Ind. 4:

194. 1883. Lectotype (designated by Shalini, Lakshminarasimhan & Arisdason, 2017:172): NEPAL, near Gosain-Than, November 1819, Wallich 1345 ( K [ K0001112812 digital image!; isolecto K [ K000830704 , K000857271 , K001112812 , K001112813 , K001112814 digital images!], G [ G00227149 digital image], G-DC [ G00135366 digital image]). Fig. 2

A climber; young stem slender brown hirsute,

hairs silky. Leaves petiolate; petiole 2–4 cm long,

terete, hairy like stem; leaf lamina lance-ovate to ovate, 8–15 × 3–6 cm, basally cordate, lobes rounded, apex narrowly acute to acuminate,

hairy on both the surfaces, more densely on abaxial surface, secondary veins 6–7 pairs, raised beneath. Inflorescence axillary capitate cyme,

8–12-flowered; peduncle 0.5–1.5 cm long, shorter than the petiole. Bracts 2, lance-ovate, 2–4 cm

long, apically acuminate, silky hairy like leaf, all bracts together form a head like inflorescence.

Calyx persistent in fruiting, c. 1.5 cm; sepals

5, oblong, lanceolate, sub-equal, herbaceous,

green, silky hairy outer, glabrous inner. Corolla campanulate to infundibuliform, 4–4.5 cm long, dark purple, corolla lobes twisted in bud, hairy on midpetaline bands. Stamens 5, included within corolla tube, un-equal, 2 long, 3 short; filaments dilated at base, glandular hairy; anthers pale white in colour. Ovary four celled; style filiform c. 2 cm long; stigma biglobose, papillate. Berries globose, c. 1 cm in diam., 2–4 seeded.

Flowering & Fruiting: October to February.

Habitat: Climbers of evergreen forests.

Distribution: India (Sikkim), and Nepal.

Etymology: The specific epithet ‘ atropurpurea ’ has its roots in Latin word ‘ ater’ meaning black and ‘ purpurea’ meaning purple; named because of dark purple flowers of the species.

Notes: The species is closely allied to Argyreia barbigera Choisy in terms of its leaf shape and leaf tomentum. It is also related to Argyreia wallichii Choisy by its capitate inflorescence.

The species was originally described as Convolvulus atropurpureus Wall. in 1832 from Nepal, with the type locality being Gosainthan near Kathmandu. Subsequently, the taxon was transferred to Ipomoea and then to Lettsomia . Raizada legitimately transferred this species to Argyreia in 1967. Staples and Traiperm (2017) listed its occurrence in India, specifically in Sikkim and West Bengal. Das and Ghosh (2004) considered this species as missing, listing it under the title ‘Plants Missing from Darjeeling Hills.’ Hence, the recent collections provide important evidence confirming its occurrence in India.

Figures

Fig. 2. Type of Argyreia atrOpurpurea (Wall.) Raizada. [© The Board of Trustees of the Royal Botanic Gardens, Kew. Reproduced with the consent of the Royal Botanic Gardens,Kew].