Impatiens kamrupana Gogoi, J.Sarma, Borah, 2019

Borah, Souravjyoti, Sarma, Jatindra & Gogoi, Rajib, 2019, Impatiens kamrupana (Balsaminaceae): a new species from Assam, India, Phytotaxa 395 (1), pp. 35-40 : 36-38

Impatiens kamrupana Gogoi, J.Sarma, Borah , sp. nov. ( Figure 1 & Figure 2 a,c,e,g,i,k,m,o,q,s)

The new species is similar to Impatiens tripetala superficially by means of its morphological appearance, flowers born in fascicles from leaf axils and shape of the flower but differs apparently due to alternate leaves, sub-bucciniform lower sepal, straight to slightly curved spur.

Type: — INDIA: Assam, Simla Reserve Forest, Nogedonga, 25°55’12.50”N, 91°18’0.40”E, 190 m a.s.l., 27 September, 2018, S. Borah & J. Sarma 0007 (holotype CAL!, isotypes CAL!, ASSAM!, GUBH!).

FIGURE 2. Comparison of Impatiens kamrupana Gogoi, J.Sarma & Borah (a, c, e, g, i, k, m, o, q, s) with Impatiens tripetala (b, d, f, h, j, l, n, p, r, t). (a–b) inflorescence, (c–d) flower bud, (e–f) lateral view of flower, (g–h) bract, (i–j) lateral sepals, (k–l) lower sepal, (m–n) dorsal petal, (o–p) lateral united petals, (q–r) pedicel with androecium, (s–t) capsules.

Annual succulent herb, sparsely branched, to 1.5 m tall; stem terete, ridged, younger stem pubescent, green, occasionally reddish in colour, nodes swollen. Leaves alternate, distributed evenly along the stem; petiole 1.5–6 cm long, pubescent, green, stipules present; leaf blade ovate to elliptic, 5–17 × 2.3–5 cm, base cuneate to attenuate, margin crenate, setose on tip of the teeth, apex acuminate, dorsally puberulent along the veins towards apex; lateral veins to 15, sub-opposite. Inflorescence axillary fascicle; peduncle 0.5–1 cm long, glabrous, bearing 3–6 flowers. Flower bud greenish white with red veins, flowers bicoloured, whitish and purple, pedicel 1–1.5 cm long, sparsely pubescent, green to reddish; bract at the base of the petiole, linear, 2–2.2 mm long, green, glabrous, caducous, apex acute. Lateral sepals 2, 3.8–4.1 × 1.5–1.7 mm, ovate, light green, apex acute, glabrous. Lower sepal sub-bucciniform, 0.4–0.5 cm deep, mouth 1–1.2 cm wide, white to yellowish white, with prominent red veins inside, beaked, beak 1–1.5 mm long; spur linear, 7–10 mm long, straight to slightly curved, swollen just above the middle, yellow, tip unifid, swollen. Dorsal petal sub-orbicular, 0.6–0.9 × 0.8–1.3 cm, apex emarginated, white, shortly beaked, dorsal side with greenish ridge, glabrous or sometime with trichomes when young. Lateral united petals bilobed, subequal, 1.7–2.8 cm long (whole), glabrous; basal lobe obovate, 0.5–0.8 × 0.9–1.2 cm, white, apex obtuse, clawed; distal lobe dolabriform, 0.6–0.9 × 1.0– 1.7 cm, purple, apex rounded; dorsal auricle distinct, 0.25–0.28 × 0.15–0.18 cm, yellow to brownish in colour. Stamens 5, 0.5–0.6 cm long, enclosing the ovary, anther lobes obtuse. Gynoecium white, glabrous, 0.4–0.5 cm long. Capsule green, turgid at middle, ridged, glabrous, 1.6–2 × 0.8 cm. Seeds 2.5–3 × 0.6–0.8 mm, rusty or brick colored, hairy.

Phenology:—Flowering (July to mid-September) and fruiting (August to October).

Habitat:— Impatiens kamrupana grows in tropical moist rocky and shady slopes in association with Amorphophallus bulbifer (Roxb.) Blume (1837: 148) , Bambusa tulda Roxb. (1832: 193) , Baccaurea ramiflora Lour. (1790: 661) , Commelina spp. , Piper attenuatum Buch. -Ham. ex Miq. (1843: 306), Tetrastigma spp. etc. The species is known only from its type locality.

Etymology:—The species epithet is named after its type locality i.e. district Kamrup of Assam state.

Distribution and threat status:—The species was found growing luxuriantly in moist tropical forest margins in Simla Reserve Forest of Assam bordering Meghalaya. Due to rapid developmental activities and widening of roads as also encroachment in the form of human habitation may cause disturbance to the natural habitat of the species in near future. Seeing the vulnerability of the species effort has be taken up to conserve the plant in live at Bamuni Gaon Social Forestry division, Kamrup District and in the Botanical Garden of Gauhati University. Further studies are required to assess its conservation status.

Additional collections (paratypes):— INDIA. Assam, Simla Reserve Forest, Nogedonga, 91°17’9.67”E, 25°55’15.5”N, 194 m a.s.l., 22 August, 2018, J. Sarma 1601 (paratype CAL, ASSAM & GUBH).

Figures

FIGURE 1. Impatiens kamrupana Gogoi, J.Sarma & Borah sp. nov. (a) inflorescence, (b–c) flower bud, (d) bract, (e) frontal view of flower, (f) back view of flower, (g–h) lateral view of flower, (i) lateral sepals, (j–l) different view of lower sepal, (m) lower sepal (inside with red venation), (n) dorsal petal (dorsal view), (o) dorsal petal (ventral view), (p) lateral united petals (dorsal view), (q) lateral united petals (ventral view), (r) pedicel with androecium, (s) gynoecium, (t) capsules, (u) dehiscing capsule, (v) seeds.