Impatiens mankulamensis K.M.P.Kumar, R. Jagad. & Nagaraj, 2017

Prabhukumar, Konickal Mambetta, Jagadeesan, Raveendran, Prasad, Gopalakrishnan, Nagaraj, Bhagavathi Amma Natarajan Achari, Kumar, Vannaratta Veettil Naveen, Bhaskar, Veeralinga & Balachandran, Indira, 2017, Two new taxa of Impatiens (Balsaminaceae) from southern parts of Western Ghats, India, Phytotaxa 296 (3), pp. 281-286 : 281-283

Impatiens mankulamensis K.M.P.Kumar, R. Jagad. & Nagaraj sp. nov. ( Figure 1 )

–similar to Impatiens travancorica Bedd. but differs from the latter by its 4–9 cm-long elliptic-lanceolate leaves, white flowers with dark purple spot at base of Lateral petal, lateral sepals elliptic-orbicular, lower sepal clearly spurred to 3 mm long, keeled and broadly ovate dorsal petal, semi flabellate distal lobe, and ellipsoid seeds. ( Table 1).

Type:— India. Kerala: Idukki, Mankulam forest, ± 1000 m, 10 November 2016, R. Jagadeesan & B. N. Nagaraj 9791 (holotype CMPR!, isotype MH!, CATH!).

Lithophytic annual herbs; stem succulent, to 25 cm tall, terete, unbranched with obscure groves, glabrous, purple. Tubers present, ca. 1 cm across, white. Leaves crowned at top or rosulate, petiolate; petiole 2–3 cm long, glabrous, translucent, purple; lamina 4–9 × 1–3.5 cm, elliptic-lanceolate to oblanceolate, tapered towards base, apex acuminate to apiculate, margin crenulate, echinate on upper surface, pubescent on lower surface when young, glabrous when mature; lateral nerves 2–3 pairs, convergent, purple, glabrous. Inflorescence a sub-umbellate cyme; peduncle 5–10 cm long, terete, glabrous; bracts 1–2, 3–3.75 × 1.5–2 mm, ovate-lanceolate, apex acuminate-mucronate, acumen ca. 1 mm long. Flowers white with dark purple spot at base of lateral petal, 1.6–2.25 cm long, glabrous, pedicellate; pedicels 5–7 mm long, glabrous, green with purple tinges. Lateral sepals 2, 4.5–5 × 2–3 mm, elliptic-orbicular, apex acuminate, white with brown tinges at tip, obscurely 3–5 nerved, glabrous. Lower sepal navicular, 8–10 × 4–5 mm, oblong-boat shaped, not peltate, apex mucronate, white with dark brown streaks, nerves obscure, glabrous, spurred; spur 2.5–3 × 0.75–1 mm, straight, chocolate brown towards tip, streaked. Dorsal petal 5–6 × 6–7 mm, broadly ovate, orbicular, apex shortly mucronate, pale purple, glabrous, keeled; keel ca. 1 mm thick, white, glabrous. Lateral petals 2, clearly stipitate; stipe 4–5 mm long, transparent, glabrous; basal lobe shorter, 3–3.5 × 2.25–2.75 mm, broadly ovate, apex mucronate, dark purple spotted, vein inconspicuous; distal lobes 8–10 × 5–6 mm, semi-flabellate, pale purple; dorsal auricle absent. Stamens 5, 3–3.5 × 1.5–1.75 mm; anthers 1–1.5 × 0.8–1 mm, cohering, white. Ovary 1–1.25 × 0.5–0.6 mm, elliptic, apex obtusely acuminate, 5-celled, stipitate, pale green, glabrous; stigma glabrous. Fruits ellipsoid, 1–1.2 cm long, glabrous. Seeds 15–25 numbers, 1 × 1 mm across, ellipsoid, compressed, both ends fringed with white hairs.

Phenology:— Flowering August–October; fruiting September–November.

Etymology:— The specific epithet “mankulamensis ” denotes the type locality in Mankulam forest, Idukki.

Distribution and Ecology:— The new species is known only from the type locality. The locality shows a rich diversity of rare and endemic plants viz. Sonerila barnesii Fischer (1938: 35) , Goniothalamus wynaadensis Bedd. (1868: 61) and Strobilanthes pulneyensis Hook. f. (1884: 438) .

Conservation status:— The new species was collected only from the type locality, i.e., Mankulam forests, Idukki. The area of occupancy is estimated to be less than 1 km ². The number of plants varies from 100–150 in the population as per the data recorded from frequent field surveys during 2013–2016. The type locality is surrounded by tea plantations in different estates. The species may face serious threats due to expansion of cultivation sites. The area should be declared by the forest department as a protected site to conserve the species. Impatiens mankulamensis is tentatively classified as Critically Endangered in accordance with IUCN (2012) (CR B1ab(i,ii,iv); 2ab(i,ii,iv); D). To confirm the percentage of decline, more field assessment is required.

Figures

FIGURE 1. Impatiens mankulamensis sp. nov. A. Habit; B.–D. Inflorescence; E. Flower bud; F.Lateral petal; G.& H. Lateral sepals; I. Dorsal petal; J. Lower sepal; J. Stamens.