Argyreia courtallensis Wight ex Choisy

P. R., Lawand & Shimpale, V. B., 2024, Revision of the genus Argyreia (Convolvulaceae) from India, Rheedea 34 (5), pp. 337-396 : 372-374

Argyreia courtallensis Wight ex Choisy in DC., Prodr. 9: 329. 1845. invalid, pro syn. Fig. 9j–m

A climber; older stem semi-woody, c. 1 cm in girth, young stem white or brown tomentose, green, terete. Leaf lamina ovate–widely ovate, 10–17 × 8–12 cm, basally shallowly cordate, apex acute or shortly acuminate, strigose above, white appressed tomentose below, secondary veins 7–9 pairs, raised prominently below; petiole 5–10 cm long, terete. Inflorescence a dichotomously branched axillary cyme, 12–16-flowered, flowers loosely arranged; peduncle shorter than the petiole 4–8 cm long, white tomentose, terete. Bracts 2–3, inflorescence bracts leafy, 3–5 cm long, petiolate, floral bracts 2, outer c. 2 cm long, lance-ovate, hairy like leaf, single veined, inner bract 1–1.5 cm long, oblong, white tomentose outside, strigose inside, persistent. Sepals 5, sub equal, c. 1 cm long, outer two narrow than inner, inner orbicular, white strigose outer, glabrous inner, persistent, enlarges in fruit. Corolla infundibuliform, rose colored outer, purple inner, hairy on midpetaline bands, corolla limb shallowly lobed. Stamens 5, unequal, 2 long c. 2.5 cm long, 3 short, 1.5–2.0 cm long; filaments white, base purple, dilated and glandular hairy at base; anther, pale pink, 4–5 mm. Ovary pale green, conical; style 1, white, c. 3 cm long; stigma biglobose, white. Young berries green, topped by remnant of style base, ripen yellow, fleshy, 1–1.5 cm across; seeds 2–4, trigonal, 5–7 mm long, white.

Flowering & Fruiting: Flowering from September to November and fruiting from December to February.

Habitat: Populations of this species are found in cool climate in evergreen or in shola forest at an altitude of 1000–1400 m.

Etymology: The species is named after type locality, Nilgiris in the southern Western Ghats.

Distribution: India (Kerala and Tamil Nadu); Endemic to Peninsular India.

Specimens examined: INDIA, Kerala, Thiruvananthapuram District, Bonaccord,

December 2016, P. R . Lawand 018 (NCK);

Thiruvananthapuram District, Ponmudi,

21.11.2017, P. R . Lawand 053 (NCK);

Thiruvananthapuram District, Palode, Madathara,

November 2017, P. R. Lawand 054 ( NCK). Tamil Nadu, Nilgiri District, Carrington to Kinnakorai , 16.06.1970, B. V. Shetty 34265 ( MH); Nilgiris

District, On the way to Ebanad, 25.07.1972, G. V .

Subbarao 41523 ( MH); Nilgiris District , On the way to Aravancadu, 29.07.1957, K. M. Sebastine 4085

(MH); Nilgiris District, Devarshola, On the way to

Naduvattam, 22.07.1960, K. Subramanyam 10533

(MH); Nilgiris District , Coonoor, 25.02.1893 ,

J.S. Gamble s.n. (MH [MH00139549]); Nilgiris

District, Gudalur Ghat, s.d., G. Bidie 1873 (MH

[MH [MH00139545]); Nilgiris District, Kateri-

Kundah Road, 1.08.1972, 1450 m, E. Vajravelu

41894 (MH [MH00139648]); Nilgiris District,

Kengarai R. F., 16.11.1970, 1825 m, E. Vajravelu

36969 (MH [MH00139646]).

Conservation status: The species is known from several localities from Kerala and Tamil Nadu. The total subpopulations observed are five and mature individuals at each population were less than 1000 and fluctuating. Further, Area of occupancy (AOO) of this species will not exceed 2000 km 2. The IUCN Red List category, Vulnerable (VU, B2b and C2ai) can be assigned to the species ( IUCN, 2024).

Notes: The species is closely related to Argyreia zeylanica (Gaertn.) Voigt. in having white tomentose lower surface of leaves, shape of inner bracts, sepals shape, fruit color but differs in possessing cordate leaves, higher number of flowers in inflorescence and large fruits.

In addition to A. nellygherya, Choisy (1845) described one more species, A. leschenalutii Choisy from the Nilgiris, based on collections Leschenault . Choisy treated two collections as two separate species viz. Argyreia nellygherya and A. leschenaultii . On careful scrutiny of type specimens, it is revealed that two species are nothing but same. Hence, A. leschenaultii is treated here as a taxonomic synonym.

Figures

Fig.9. Argyreia maSterSii (Prain) Raizada (a-e): a. Habit;b. A cut flower withstamens and stigma;c. Bracts;d. Sepals;e. Infrutescence. Argyreia mOlliS (Burm.f.) Choisy (f-i): f. Habit;g. Inflorescence;h. Leaf abaxial surface;i. Sepals.Argyreia nellygherya Choisy (j-m): j. Fruiting twig;k. Flowering twig; l. Bracts;m. Sepals.