Dubyaea atropurpurea Stebbins, J. Bot.

S., Dey & H. A., Barbhuiya, 2023, Dubyaea atropurpurea (Asteraceae): an addition to the flora of India, Rheedea 33 (2), pp. 92-96 : 92-94

Dubyaea atropurpurea Stebbins, J. Bot. 75: 51. 1937, Mem. Torrey Bot. Club 19(3): 14. 1940; C. Shih & N. Kilian, Fl. China 20–21: 337. 2011. Lactuca atropurpurea Franch., J. Bot. (Morot) 9(16): 294. 1895, nom. illeg. Type: CHINA, Yunnan, at the top of Tsang-chan, above Tali , alt. 4000 m., J.M. Delavay 1001 (Holo P? [not traced]). Fig. 1

A perennial herb with stout taproot, up to 80 cm high. Stem green, stout, erect, covered with long stiff purplish hairs, blackish when dried. Leaves mostly cauline, 10‒25 × 3‒6 cm; lower ones large, lyrate-pinnatifid, sessile, blade glabrous above, sparsely short hirsute along the veins beneath; upper ones elliptic, sinuatedentate, usually cordate-clasping at base. Capitula purplish, 3‒8, drooping on elongate, densely purplishhirsute peduncles, c. 5 cm across, 60‒70-flowered. Involucral bracts in several series, the outer narrowly lanceolate or linear, c. 25 × 3 mm, acuminate at apex, the inner shorter, broadly lanceolate, 4‒5.5 mm broad, all greyish-purple, long-hirsute along midrib. Corolla greyish-purple, 10‒15 mm long; tube 2‒3 mm long. Stamens 5; filaments free, ribbon-like, c. 5 mm long; anthers fused together to form a tube-like structure surrounding the style, 4‒5.5 mm long, yellowish. Ovary oblong to fusiform, up to 6 mm long; style c. 15 mm long; stigmatic lobes 1.5‒2.5 mm long. Achenes oblong or somewhat fusiform, 4‒6 mm long, shallowly ribbed; pappus bristles 1‒2-seriate, plumose, yellowish, 6‒10 mm long.

Flowering & fruiting from July to September.

Habitat: The species grows on an alpine meadow at an altitude of 3678 m. Only four mature individuals were spotted during the entire field survey. The associated species include Cremanthodium reniforme (DC.) Benth. , Ligularia kingiana (W.W.Sm.) R.Mathur , L. fischeri (Ledeb.) Turcz. (all Asteraceae ), Morina nepalensis D.Don ( Caprifoliaceae ), Cyanotis vaga (Lour.) Schult.& Schult.f. ( Commelinaceae ), Rhodiola yunnanensis (Franch.) Fu ( Crassulaceae ), Geranium sp. ( Geraniaceae ), Epilobium sp. ( Onagraceae ), Hemipilia chusua (D.Don) Y.Tang & H.Peng ( Orchidaceae ), Pedicularis pantlingii Prain ( Orobanchaceae ), Bistorta macrophylla (D.Don) Soják ( Polygonaceae ), and Rosa sericea Lindl. ( Rosaceae ) ( Fig. 1a ).

Distribution: India , China, Myanmar ( Stebbins, 1940; Zhu & Kilian, 2011) ( Fig. 2 ).

Specimen examined: INDIA , Nagaland, Kiphire district, Mt. Saramati peak, c. 3678 m, 04.08.2021, S . Dey s.n. ( HBARC [ HBARC00006632 ]) .

Conservation status: Dubyaea atropurpurea is a rare species, so far known from a few (≤10) locations. The Extent of Occurrence is estimated to be less than 20,000 km 2. Also, there is continuing decline of Area of Occupancy due to habitat degradation resulting from various anthropogenic activities. Hence, following IUCN (2012, 2022) this species is categorised as Vulnerable (VU B1ab(ii)).

Notes: Dubyaea atropurpurea shows close affinity with D. forrestii Mamgain & R.R.Rao in general appearance. However, the former is distinguished from the latter in having hirsute stems, lyrate-pinnatifid leaves, densely hirsute peduncles, larger involucres, involucral bracts in several series, and non-compressed achenes. Whereas, in D. forrestii the stems and peduncles are glabrous, cauline leaves broadly pinnatisect and sub-glabrous, involucres smaller, involucral bracts in 2–3 series and the achenes compressed (Mamgain & Rao, 2008). The Indian taxa of the genus Dubyaea can be identified by using the following key.

Figures

Fig. 1. Dubyaea atropurpurea Stebbins: a. Natural habitat; b. Habit; c. Portion of ventral surface of leaf and young capitulum; d. Top view of an open capitulum (from S. Dey s.n.; photos by S.Dey).

Fig. 2. Distribution map of Dubyaea atropurpurea Stebbins: Solid circle () indicates previously known localities, and solid square () indicates the currently reported locality. Map created with SimpleMappr (Shorthouse, 2010).