Impatiens nagorum Gogoi, Moaakum & S.Dey, 2017

Impatiens nagorum Gogoi, Moaakum & S.Dey View in CoL sp. nov. ( Figure 1–3 View FIGURE View FIGURE 2 View FIGURE 3 , Tab. 1 View TABLE 1 )

Diagnosis: —close to Impatiens xanthinoides G.W. Hu (262: 2015) in small stature and general shape of flower, particularly the small basal lobe of the united lateral petals and large distal lobe, as well as fusiform capsule but differs in leaf margin serrate, inflorescence up to 5 flowers, flowers purple, lateral sepals hairy, deeper lower sepal, gradually tapering into a hooked non linear spur, dorsal petal narrowly elliptic when seen from the bottom, green with red veins and flushed with pink; basal lobe of lateral united petals inconspicuous.

Type: — INDIA, Nagaland, Kiphire district, Fakim Wildlife Sanctuary , 2336 m. a.s.l., 25°48’24.6”N – 094°59’20.8”E, 08.10.2016, Moaakum & Santanu Dey MOAZ086 (holotype: CAL! GoogleMaps , isotypes: CAL! GoogleMaps & ASSAM! GoogleMaps ).

Sparsely branched perennial, up to 35 cm tall. Stem terete, dull red, slightly ridged, nodes not swollen. Leaves confined only to upper parts, alternate, petiole to 3.5 cm long, green, stipule absent; lamina narrowly elliptic, 2.5-6.5 × 1.5-2.5 cm, usually glabrous, base cuneate, apex acuminate, margin serrate, setose at the tip of the teeth, lateral veins up to 7 pairs, sub-opposite. Inflorescence axillary, subumbellate, peduncle to 3 cm long, 1-5 flowered, bud pinkish green. Flower purple, pedicel to 1 cm long, green, bract at the base lanceolate, slightly hairy, green, 1 mm long, persistent, apex acute, mid-vein non prominent. Lateral sepals 2, lanceolate, partially translucent, slightly hairy, 3 mm long, 1 mm wide at base, apex acuminate, margin entire. Lower sepal white with dull red veins outside, with yellowish markings inside, navicular, to 7 mm deep, mouth without beak, gradually tapering in to a non-linear hooked spur; spur dull red, to 8 mm long, tip unifid. Dorsal petal galeiform, green with red veins and flushed with pink, to 7 × 6 mm, apex acute, dorsally not ridged. Lateral united petals purple, bilobed, unequal, to 1.5 cm (whole), distinctly clawed, basal lobe whitish pink, inconspicuous, triangular, 1 mm wide, 1 mm long, apex obtuse, auricle absent, distal lobe purple, dolabriform, to 1 cm long, to 0.7 cm wide. Stamens slightly curved, whitish, to 3 mm long, anther lobes acute. Capsule green, fusiform, to 1.2 cm.

Distribution: — Impatiens nagorum is known only from its type locality, i.e. in the peripherial zone of Fakim Wildlife Sanctuary of Kiphire district of Nagaland with a population of ca. 20 individuals.

Ecology & Habitat: — Impatiens nagorum grows in moist temperate broadleaved forest in shady places under tree canopy along with Corydalis borii , Elatostema sp. , Laportea bulbifera , Strobilanthes sp. , Lithocarpus sp. , Engelhardtia sp. , ferns, bamboos.

Phenology: —Flowering and fruiting observed in October.

Etymology: —The species epithet is chosen to denote the indigenous people, i.e. the Naga tribe of Nagaland, the local inhabitants in the type locality of the species.

Similar species: —Morphologically Impatiens nagorum is similar to Impatiens xanthinoides due to small stature and shape of the flower, particularly galeiform dorsal petal but leaf margin serrated, higher number of flowers in the inflorescence, purple flowers, hairy lateral sepals, deeper lower sepal gradually tapering into a hooked spur, dorsal petal narrowly elliptic when seen from the bottom, green with red veins and flushed with pink, inconspicuous basal lobe of lateral united petals as well as serrated leaf margins make it different from the latter ( Tab. 1 View TABLE 1 ). I. xanthina H. F. Comber (1934: 248) has narrowly lanceolate leaves, 1-2 flowered inflorescences, yellow suborbicular dorsal petal, abaxially puberulent, purple- or red-tinged at base of the dorsal petal, basal lobes of lateral united petals much larger, orbicular with purple- or red-tinged flecks at base and distal lobes dolabriform or ovate-dolabriform with obtuse apex ( Tab. 1 View TABLE 1 ).

Palynology: —Pollen grains of Impatiens nagorum are ±rectangular in polar view, 34.769 –37.258 × 20.446 – 23.026 μm (P [polar length] × E [equatorial length]), in polar view, 4-colpate, with long and thin colpi, sexine with irregular reticulate ornamentation with bulky reticulate walls, and numerous granules in lumina can be seen at high magnification ( Figure 3 View FIGURE 3 : A&B). Pollen grains of Impatiens xanthinoides are subellipsoid in polar view, 25.4–27.8 × 18.3–19.5 (P [polar length] × E [equatorial length]) μm, 4-colpate, with long and thin colpi, exine with irregular reticulate ornamentation with thin reticulate walls, and sparse granules in lumina can be seen at high magnification ( Cai et al. 2015).

Seed micromorphology: —Seeds of Impatiens nagorum are obovoid, 1.348 × 0.761 mm, ratio of L/W (length/ width) 1.77:1, some of the epidermal cells significantly form cristate protrusions which are sub-spherical to oblong with distinct deposition of granules without forming any ring ( Figure 3 View FIGURE 3 C-E), and irregularly oblong multigonal cuticular granules cover the nonprotrusive epidermal cells ( Figure 3 F View FIGURE 3 ). Seeds of Impatiens xanthinoides are also obovoid, 0.93–1.43 × 0.62–0.88 mm, ratio of L/W (length/width) 1.50–1.63, some of the epidermal cells significantly forming cristate protrusions which are spirally thickened, and with fine cuticular granules densely covering the nonprotrusive epidermal cells ( Cai et al. 2015).