Impatiens omissa Hooker (1906: 43

Anirudhan, Anitha Melesuparambil, Mani, Bince, Gnanasekaran, Gunadayalan & Thomas, Sinjumol, 2023, Rediscovery of Impatiens parvifolia and reinstatement of I. omissa (Balsaminaceae) in India, Phytotaxa 589 (3), pp. 269-277 : 271-273

Impatiens omissa Hooker (1906: 43 , 48). ( Figs. 2–3 )

Lectotype:— INDIA. Tamilnadu: Pulney [Palani] Hills (West), s.d., Beddome s.n. ( MH00003296 !), designated by Singh (2016).

Annual, semi-erect or diffuse herbs up to 20 cm long; stems more or less quadrangular, slender, branching at base, red, canaliculated, pubescent at nodes; extra-floral nectary absent. Leaves opposite or alternate; petiole to 10 mm long, channeled above, upper leaves are often sessile; blade ovate, 8–16 × 8–12 mm, base truncate, apex acute, margins serrate, adaxial surface pubescent, abaxial surface glabrous, midrib distinct, 3–5 ribbed basally, lateral veins not prominent. Inflorescence 2.5–5.0 cm long, pedunculate sub-umbels or racemes. Bracts linear, ca. 2 mm long, pale green. Flowers 3–6 in each peduncle, 8–15 mm across, white; pedicel to 3 cm long, pale green, glabrous; lateral sepals 2, ovate, slightly oblique, ca. 2 × 1 mm, glabrous, green with red tinge; dorsal petal suborbicular or elliptic, ca. 6 × 5 mm, glabrous, dorsally keeled, mucronate; lateral united petals 2-lobed, 14–17 × 7–10 mm, glabrous, white; basal lobe elliptic, ca. 5 × 3 mm, bright crimson stripes present; distal lobe ca. 14–17 × 7–10 mm, 2-blobed, rarely entire; dorsal auricle filiform, 3–4 mm long, yellow or bright orange; lower sepal ca. 6 × 4 mm, boat-shaped, glabrous, apex cuspidate; spur tubular, 4–6 mm long, glabrous; Stamens 5, cohering above pistil; column ca. 1.5 × 1.5 mm, slightly curved; filaments 5, white, connate at apex; anthersred. Pistil ca. 1 × 1 mm; ovary narrowly oblong, glabrous; style rudimentary; stigma 5-toothed. Capsule ellipsoid, ca. 7 × 4 mm, glabrous, green; seeds ovoid, 7–15 in number, ca. 1.5 × 1.0 mm, pubescent.

Phenology: —September to December.

Habitat and distribution: —Grows on wet and dripping open rocky slopes in montane grasslands at an elevation of 1800–2200 m in Anamalai hills, Palani hills, Megamalai hills and Travancore high ranges. This species grows in association with Smithia sp. , Eriocaulon sp. and mosses.

Taxonomic Notes: — Hooker (1906) described I. omissa from the erroneously identified specimens of I. parvifolia Bedd. collected from Pulney Hills (Beddome s.n., MH00003296!; K000683310, image!) and Anamallays (Beddome s.n. MH00003298!). In all these specimens, Hooker illustrated the plant habit, leaves, and dissected floral parts such as lateral sepals, dorsal petal, lateral united petals, lower sepal with spur, and seeds. The diagnostic characteristic features of I. omissa such as boat-shaped lip with a long spur (4–6 mm long), a lateral united petal with a dorsal auricle as long as the spur, a shallowly lobed distal lobe of the lateral united petal, and a stripped basal lobe of the lateral united petal were found to match exactly with our fresh collections made from the Anamudi hills, and Devikulam in the Idukki district of Kerala. Therefore, based on the fresh and herbarium specimens the name I. omissa is reinstated here as a distinct species.

Specimens examined: — India, Kerala: Idukki district, Travancore high range, Anaimudi , Sep 1933, Barnes 494 ( MH) ; Anaimudi, 19 Nov 1965, Shetty 26530; Devikulam , 12 Sept 2019, Anitha and Bince 68960 ( RHT) ; Anaimudi , 5 Sept 2021, Anitha and Bince 68963 ( RHT) . Tamil Nadu: Coimbatore district, Pulney Hills ( West ), s.d., s.coll. s.n. ( K000683310 , image!); 1873, s.coll. s.n. ( MH00003296 !) ; s.d., Beddome s.n., ( MH00003297 !) ; Anamallay’s, 1870, Beddome s.n. ( MH00003298 !) ; Theni district, Megamalais, Vattaparai , 17 Nov 1990, Lakshmanan 94375 ( MH!) .

Figures

FIGURE 2. Impatiens omissa:Habitat (A) and habit (B).

FIGURE 3. Impatiens omissa:A-B. Inflorescence, C. Lateral sepals, D–E. Lower sepal, F.Dorsal petal, G–H. Lateral united petal, I. Pistil and stamen, J. Fruit, K. Seeds.