Impatiens saulierea B. Mani, S. Thomas & 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 : 234-236

Impatiens saulierea B. Mani, S. Thomas & S. J. Britto sp. nov. ( Fig. 1 )

The proposed new species is morphologically allied to Impatiens diversifolia , but differs in having upright and stiff stems, salmon-red and forked stipules, linear leaves, 2–3-flowered axillary fascicles, pink flowers, 5–6 mm long falcate lateral sepals, saccate lips without a yellow blotch, a straight spur which is longer than the wing (lateral united) petals, widely elliptic and pubescent standard petals, non-stipitate and obovate dorsal lobes of wing petals, an obovate basal lobe of the wing petals, a yellow dorsal auricle, terete pollen grains with more than 4-colpi and with an irregularly baculate pollen reticulum, long and fusiform capsules, and sub-globose seeds.

Type:— INDIA. Kerala: Kozhikode District, Kakkayam, 680–720 m, 11 October 2016, Mani et al. 68152 (holotype RHT!, isotypes MH!, RHT!).

Description

Terrestrial, slender, erect annual herb, 40–70 cm tall, branched; stem angled–terete, green, salmon-red tinged, glabrous, nodes slightly swollen. Leaves opposite, decussate, petiolate, stipulate; stipules persistent, salmon-red, forked; petiole 2–4 mm long; lamina 4.5–8 cm long, 5–9 mm wide, linear, base rounded, margin serrate, narrowly acute at apex, lower surface whitish-green, glabrous, upper surface green, pubescent, midrib distinct, lateral veins obscure. Inflorescence 2–3 flowered in axillary fascicles. Flowers 1.6–1.8 cm across; bract basal, ca. 2 × 0.5 mm, narrowly triangular, salmon-red; pedicel 2.3–3.5 cm long, salmon-red, pubescent along one side. Lateral sepals 2, 5–6 × 0.5–1 mm, falcate, glabrous, pink, apex ca. 1 mm long, mucronate; lower sepal 6–7 × 3–3.5 mm, saccate, glabrous, pale pink, 1 mm long, mucronate at apex, spur 1.8–2.3 cm long, pale pink, straight, glabrous; dorsal petal 5–5.5 × 6.5–7.5 mm, widely elliptic, pubescent, pink, mid-vein green-tinged, apex obtuse, 1 mm long, mucronate; lateral united petals 12–16 × 6.5–9.5 mm, bilobed, pink, basal lobe 2–3 × 1–1.5 mm, obovate, much smaller than distal lobe, distal lobe 10–14 × 6.5–9.5 mm, obovate, glabrous, auricle short, rotund, yellow. Stamens 5, cohering above pistil, column ca. 3 × 2 mm, slightly curved; filaments 5, pink, narrow and free at base, broad and connate towards apex, ventral filaments shorter; anther ca. 0.5 × 0.25 mm, pollen pink, terete. Pistil ca. 2.5 × 1.5 mm, lanceovate, glabrous, carpels 5, ovules 4 in 3–4 locules and 3 in 1–2 locules, on axile placentae; style rudimentary; stigma 5-toothed. Capsule 12–24 × 4–5.5 mm, fusiform, ridged, glabrous–sparsely pubescent, green–salmon-red, scar present at base of dorsal side; pedicel 3.2–4.0 cm long, horizontal–reclined in fruit, seeds 16–19 in number, ca. 2 × 1.25 mm, sub-globose, caruncle present, glabrous, black, shining.

Etymology:— Impatiens saulierea is named in honour of Fr. Sauliere who botanised in the Anglade Institute of Natural History (AINH), Shembaganur, Kodaikanal, a hill laboratory of RHT.

Phenology:— Flowering and fruiting just after the southwest monsoon season, September–October.

Habitat and distribution:— Grows along with Impatiens gardneriana Wight (1846: 1050) on wet and dripping open rocky slopes in the ever green forests at elevation of 680–720 m a.s.l. The new species is known only from the hill ranges of Kakkayam, Kozhikkode district in Kerala.

Preliminary conservation status:— The present study made known that Impatiens saulierea shows an extent of occurrence of less than 100 km 2, the area of occupancy is less than 10 km 2, number of mature individuals are less than 250 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. saulierea is assessed as belonging to the Endangered (EN) category.

Taxonomic notes:— Impatiens saulierea shows similarity to I. diversifolia , but differs from the latter by various morphological characteristics which are depicted in Table 1. I . diversifolia prefers to grow in marsh habitats around or above 1000 m a.s.l. and often grows as a diffuse annual or perennial herb. On the other hand, the new species grows on wet and dripping rocky slopes and the plants are upright and strict annual herbs. Again, I. diversifolia is characterised by the presence of a yellow eye (blotch) in the lip, with an often curved or S-shaped and forked spur which is equal to the length of the wing (lateral united) petals and a stipitate dorsal lobe of the wing petals. Conversely, a lip without eye (blotch), straight and unforked spur which is longer than the wing petals, and a non-stipitate dorsal lobe of the wing (lateral united) petals are also key diagnostic characteristics of I. saulierea . Moreover, petiolate and linear leaves, round leaf bases, dorsally pubescent laminas, a pedicel being shorter than subtending leaves, and a long, fusiform capsule with 16–19 seeds are also important morphological characters useful to discriminate it from allied species.

† Bhaskar 2012

Figures

FIGURE 1. Impatiens saulierea (A–R) and I. diversifolia (S–T). A. Habit; B. Flowering branch; C. Node region shows petiolate leaves, forked stipules & bracts; D. Single flower; E. Flower: front view; F. Flower: ventro-lateral view; G. Lateral sepals; H. Lower sepal with straight spur; I. Saccate lower sepal; J. Dorsal petal: lateral view; K. Standard petal: dorsal view; L. Lateral united petals (inset: yellow dorsal auricle); M. Androecium (inset: pistil); N. Fruit; O. Fruit: dehisced; P. Seeds; Q. Scanning electron micrographs (SEM) of entire terete pollen; R. Reticulate sexine under high magnification; S. Flower with S-shaped spur; T. Flower: front view shows stipitate lateral united petals and yellow eye on lower sepal.