Impatiens josephia S. Thomas, B. Mani & S. J. Britto, 2018

Mani, Bince, Thomas, Sinjumol & Britto, S. John, 2018, Two new species of Impatiens (Balsaminaceae) from the Western Ghats, India, Phytotaxa 334 (3), pp. 233-240 : 236-239

Impatiens josephia S. Thomas, B. Mani & S. J. Britto sp. nov. ( Fig. 2 )

The proposed new species is morphologically allied to Impatiens aliciae , but differs in having erect, quadrangular and stiff stems, salmon-red stipules, linear leaves, 3–5 flowered axillary fascicled inflorescences, falcate and pubescent (mid-vein) lateral sepals, a boat-shaped lip with an orange blotch at the centre, a widely obovate dorsal lobe of the wing petals, a short dorsal auricle which is ¼ the length of the wing (lateral united) petals, rod-shaped pollen grains with polar colpi, fusiform and long pedicellate capsules, and slightly reniform–discoid seeds.

Type:— INDIA. Kerala: Idukki District, Idukki, 940–1000 m, 08 October 2016, Thomas et al. 68212 (holotype RHT!, isotypes MH!, RHT!).

† Bhaskar 2012

Description

Terrestrial, upright, annual herb, 30–55 cm tall, branched, branches erect; stem quadrangular, pale green, glabrous. Leaves opposite, decussate, stipulate, stipule salmon-red, ca. 2 mm long, petiolate; lamina 4.8–7.4 cm long, 4.5–5 mm wide, linear, base rounded, margin serrate, narrowly acute at apex, upper surface green, pubescent, lower surface whitish-green, glabrous, midrib distinct, lateral veins obscure. Inflorescence 3–5 flowered in axillary fascicles. Flowers 8–10.5 mm across; bract ca. 1 × 0.5 mm, narrowly triangular, caducous, pale green, situated at base of pedicel; pedicel 2.5–4 cm long, pale green, sparsely red-tinged, pubescent along one side. Lateral sepals 2, 4–5 × ca. 0.5 mm, falcate, mid-vein puberulent, pink, green towards apex, apex ca. 0.25 mm long, mucronate; lower sepal 4.5–5 × ca. 2.5 mm, boat-shaped, glabrous, white–pale pink with a prominent orange blotch at the centre, apex cuspidate, spur ca. 3.5 × 1 mm, tubular, straight, glabrous, pink, yellow towards apex, shorter than the wing (lateral united petals) petals; dorsal petal 4–4.5 × 4–4.5 mm, orbicular, mid-vein pubescent, pink, dorsally keeled, apex retuse, ca. 0.5 mm long mucronate; lateral united petals 9–10 × ca. 5 mm, bilobed, pink, basal lobe ca. 3 × 1.5 mm, falcate, much smaller than distal lobe, distal lobe 7–7.5 × ca. 5 mm, widely obovate, glabrous, auricle prominent, 2.5 mm long, filiform, purple, ¼ the length of the wing. Stamens 5, cohering above pistil, column ca. 2 × 1.25 mm, slightly curved; filaments 5, white, narrow and free up to ⅔ their length, broad and connate at apex, ventral filaments shorter; anther ca. 0.5 × 0.25 mm, pollen white, rod-shaped. Pistil ca. 1.5 × 0.5 mm, narrowly oblong, glabrous, slightly curved, pale green, ovules 3–4 in each locule, on axile placentae; style rudimentary; stigma 5-toothed. Capsule 12–15 × ca. 4 mm, fusiform, asymmetrical, glabrous, green, scar present at base of dorsal side; pedicel 3.0– 4.8 cm long, horizontal–reclined in fruit, seeds 11–15 in number, ca. 1.75 × 1 mm, slightly reniform–discoid, glabrous, black, shining, with caruncle present.

Etymology:— The name I. josephia has been chosen in accolade of St. Joseph’s College, Tiruchirappalli, which is one of the pioneer and foremost educational institutions in India.

Phenology:— Flowering starts from end of August and lasts up to October. Fruits matured during September– November.

Distribution and preliminary conservation status:— The new species is known only from the hill ranges of Idukki, Idukki district in Kerala. It grows on wet and dripping rocky slopes in the evergreen forests at an elevation of 940–1000 m a.s.l. Impatiens josephia shows an extent of occurrence that is estimated to be less than 100 km 2, the area of occupancy is less than 10 km 2, with a continuing decline observed in the quality of habitat, the number of mature individuals are less than 250 with an observed continuing decline and the number of mature individuals in each subpopulation is less than 50 (IUCN 2016). By following IUCN criteria for assessing the conservation status, I. josephia is assessed as belonging to the Endangered (EN) category.

Taxonomic notes:— Impatiens josephia resembles I. aliciae in its herbaceous habit, shortly petiolate and serrate leaves, lamina with indistinct lateral veins, axillary flowers, pedicel pubescence, small flowers, and orbicular standard petal. However, it differs from the latter by various morphological characteristics ( Table 1). I. aliciae , an annual herb, often grows as a procumbent plant characterised by having a short root stock, narrowly elliptic-oblong leaves, axillary 1 or 2-nate flowers, cymbiform lower sepal (lip), 2–3 mm long spur, obovate dorsal lobe of wing petals, 5.5 mm long dorsal auricle which is half as long as the wing (lateral united) petal, bilateral pollen grains, ellipsoid capsules and sub-globose seeds. Alternatively, I. josephia is an upright plant with stiff and quadrangular stems, salmon-red stipules, linear and dorsally pubescent leaves, 3–5-flowered axillary fascicled inflorescences, long pedicellate flowers, falcate lateral sepals with pubescence on mid-veins, boat-shaped lips with an orange blotch, ca. 3.5 mm long spur, widely obovate dorsal lobe of wing petals, a ca. 2.5 mm long dorsal auricle which is only ¼ as long as the wing (lateral united) petal, rod-shaped pollen grains, fusiform capsules and slightly reniform–discoid seeds.

Figures

FIGURE 2. Impatiens josephia. A. Habit; B. Flowering and fruiting branch; C. Node region shows petiolate leaves, salmon-red stipules & fascicled inflorescence; D. Lateral sepals; E. Lower sepal (inset: orange blotch at centre); F. Standard petal: lateral view; G. Standard petal: dorsal view; H–J. Lateral united petals; K.Androecium; L. Pistil; M. Fruit; N–O. Seeds; P. SEM micrographs of entire pollen grain; Q. Reticulate sexine under high magnification.