Impatiens panduranganii K.M.P.Kumar, R. Jagad. & G. Prasad, 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 : 285

Impatiens panduranganii K.M.P.Kumar, R. Jagad. & G. Prasad sp. nov. ( Figure 2 )

-similar to Impatiens travancorica Bedd. but differs from the latter by its milky white flowers, lateral sepals elliptic-oblong, dorsal petal elliptic-ovate, absence of spur in lower sepal, distal lobe in lateral petals without spreading, ellipsoid capsule, and ovoid-ellipsoid seeds. ( Table 1).

Type:— India. Kerala: Idukki, way to Edamalakudy, Pettimudi, ± 2050 m, 19 August 2016, K. M. Prabhukumar& R. Jagadeesan 9501 (holotype CMPR!, isotype MH!, CATH!).

Erect annual herbs, lithophytic plants; stem succulent, to 20 cm tall, cylindrical, unbranched with shallow groves, glabrous. Leaves crowned at top or rosulate, petiolate; petiole 0.8–4.5 cm long, glabrous, transparent; lamina elliptic-ovate, 2.5–4 × 1.5–2.5 cm, base shortly attenuate, apex obtuse-apiculate, margin crenulate, echinate on upper surface, glabrous beneath with purple tinges, green; midrib conspicuous, lateral nerves 4 pairs, convergent. Inflorescence an umbellate cyme; peduncle 4–6 cm long, glabrous; bracts 2–3 from the pedicel base, 3.5–4 × 1.8–2 mm, ovate-lanceolate, apex acuminate, mucronate. Flowers pedicellate, milky white, 1.8–2 cm long; pedicels 1.5–2 cm long, glabrous. Lateral sepals 2, 5–6 × 2–3 mm, elliptic-oblong, apex shortly acuminate, glabrous, white with green tinges at tip, distinctly 3-nerved. Lower sepals navicular, 7–9 × 4–6 mm, peltate, elliptic, apex mucronate, white with yellow tinges, nerves prominent at base, glabrous, spur absent. Dorsal petal 8–12 × 7–10 mm, elliptic-ovate, white, glabrous, not keeled. Lateral petals 2, clearly stipitate, 3–4 mm long stipe, glabrous; basal lobe smaller, 2.5–3 × 2–2.2 mm, ovate, apex acuminate, veins conspicuous; distal lobes 1 × 1 cm, shoe-shaped, white with minute light purple dots; dorsal auricle ca. 1 mm long, yellow.Anthers 2 × 2 mm across, white, glabrous. Ovary 2.2–2.5 × 0.8–1 mm, stipitate, tapering towards both ends, glabrous; stigma glabrous. Fruits ellipsoid, 0.8–1.2 cm long, glabrous. Seeds 15–20, compressed, 1 × 1 mm across, ovoid-ellipsoid, both ends with white hairs. Seed hairs confined to either ends of seed, c. 5 hairs each end with simple spiral banding.

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

Etymology:— The species is named in honour of Dr. A. G. Pandurangan, Scientist F & Head PS & ES Division, JNTBGRI, Thiruvananthapuram for his immense contributions to the South Indian Balsaminaceae and Indian plant taxonomy.

Distribution and Ecology:— The new species is known only from the type locality. The locality shows a rich diversity of rare and endemic balsams viz. Impatiens coelotropis C.E.C. Fisch. (1934: 390) , I. disotis Hook.f. (1906: 48) , I. johnii Barnes (1939: 102) , I. latifolia L. (1753: 937), I. leschenaultii (DC.) Wall. ex Wight & Arn. (1834: 136) , I. modesta Wight (1837: 13) , I. phoenicea Bedd. (1858: 175) and I. platyadena C.E.C. Fisch. (1934: 393) .

Conservation status:— The area of occupancy is estimated to be less than 2 km ². The number of plants varies from 200–350 in the population in the type locality of the species. Impatiens panduranganii is tentatively classified as Critically Endangered in accordance with IUCN (2012) ( CR B1 ab(i,ii,iv); 2ab(i,ii,iv); D). The major threat observed was the construction of a road in the grasslands to various settlements at Edamalakudy area of Kerala state. There is a strong chance that 60–80% of the population will disappear from the locality if the work is continued. Based on field observations since 2012, the third author reported 10%–20% population decline in the type locality mainly due to disturbance in the grasslands .

Additional specimens examined (paratypes): — India. Kerala: Idukki, way to Edamalakudy, Pettimudi, ± 2050 m, 29 August 2016, R. Jagadeesan 9570 (CMPR!).

Figures

FIGURE 2. Impatiens panduranganii sp. nov.A.–C. Habit; D. Single flower; E. Base of inflorescence; F. Lateral sepals; G. Lateral petals; H. Dorsal petal; I. Lower sepal; J. Stamens; K. Ovary; L. Fruit; M. Dehisced fruit showing seeds.