Impatiens paramjitiana Gogoi & Borah, 2014

Gogoi, R. & Borah, S., 2014, Impatiens paramjitiana, a new species of Balsaminaceae from Arunachal Pradesh, India, Phytotaxa 175 (3), pp. 171-175 : 171-174

Impatiens paramjitiana Gogoi & Borah , sp. nov. ( Fig. 1 and 2 )

Similar to I. apsotis Hook. f. (1911: 2972) in general floral shapes but differs having spirally arranged leaves, shallowly serrate leaf margins, deep purple flowers, lateral sepals purple, capsule turgid at the middle.

Type: — INDIA. Arunachal Pradesh: West Siang district, crossing the Army camp towards Daporijo from Along , 300–400 m, 1 August 2013, R . Gogoi 30538 (holotype CAL!, isotypes ASSAM!, ARUN!) .

Perennial non succulent herbs, unbranched or sparsely branched, to 70 cm tall. Stem terete, slightly ridged, purplish; nodes not swollen. Leaf confined to upper portion of the stem, spirally arranged; petiole 1.5–10 cm long, purple, with few pairs of filiform glands; stipule absent; lamina 2.5–12 × 1–6 cm, simple, elliptic, glabrous, shiny, velvety; veins to 12 pairs, sub-opposite, main vein purplish at base; base cuneate; apex acute to slightly acuminate;, margin crenate, setose between teeth. Inflorescence axillary; single flowered, peduncle 2–2.5 cm long, pink; bract ca. 0.7 × 0.5 cm, ovate, situated at the base of the pedicel, persistent, green. Sepals: lateral sepals 2, ca. 0.8 × 0.6 cm, obliquely ovate, glabrous, purple; transparent, membranous; lower sepal navicular, tapering in to a spur, white with purple streaks, to 1.5 cm deep, mouth slightly beaked, beak to 1 mm, spur to 2.5 cm, linear straight to slightly bending in ward, tip white. Petals: dorsal petal ca. 1.2 × 0.8 cm, ovate, apex acute to slightly emarginated, non beaked, shallowly cucullate, purple; lateral united petals to 1.5 × 0.6 cm (whole), bilobed, unequal, purple, without any blotches, basal lobe unevenly triangular, apex obtuse, not clawed, distal lobe unevenly dolabriform, apex rounded, to 0.9 × 0.6 cm, auricle present at the base, golden yellow, to 1.5 mm long, margin entire; stamens to 4 mm long; anther lobes obtuse. Capsule to 1.5 × 0.5 cm, turgid at middle, ridged, glabrous, green; seeds many, to 1.5 mm in diameter, greenish white, surface papillose. ( Fig.1–2 )

Phenology: flowering and fruiting in July–September.

Distribution and habitat: Impatiens paramjitiana grows at low elevation (ca. 400 m.) in moist shady areas and only one small population was encountered in the type locality.

Etymology: The species is named after Dr. Paramjit Singh, distinguished Indian scientist and director, Botanical Survey India for his contribution to Indian plant taxonomy.

Conservation status:— Impatiens paramjitiana is assessed as Critically Endangered (CR) according to the IUCN Red List criteria ( IUCN 2010). There was only a small population found road side of about 50 individuals. The habitat is disturbed heavily by urbanization and agricultural activities.

Notes: Impatiens paramjitiana does not have close affinity to any of the Indian Impatiens but is close to the Chinese species I. apsotis Hook. f. (1911: 2972) in general floral shape. It differs significantly from the latter species in its spirally arranged leaves, shallowly serrated leaf margins, deep purple flowers, lateral sepals purple, capsule turgid at the middle ( Table 1). On the other hand, one species from neighbouring Myanmar, I. pritchardii Toppin (1920: 360) , also shows some superficial similarity with the new species, but I. paramjitiana is different from the later in having velvety leaves, single deep purple flower in each peduncle, navicular lip with straight spur ( Table 1).

Figures

FIGURE 2. Impatiens paramjitiana: A. habit; B. flowering twig; C. flower; D. lateral sepals (ventral); E. lateral sepals (dorsal); F. dorsal petal (ventral); G. dorsal petal (dorsal); H. lateral united petals (ventral); I. lateral united petals (dorsal); J. lower sepal with spur; K. pedicel with stamens and ovary; L. fruit with pedicel and bract; M. seeds.

FIGURE. 1. Impatiens paramjitiana: A. flowering twig; B. flower; C. lateral sepals (ventral); D. lateral sepals (dorsal); E. dorsal petal (ventral); F. dorsal petal (dorsal); G. lateral united petals (ventral); H. lateral united petals (dorsal); I. lower sepal with spur; J. pedicel with stamens and ovary; K. fruit with pedicel and bract (Drawn by Dr. H. A. Barbhuiya).