Impatiens shailajae Sindhu Arya & Kumar V.S.A., 2021

Arya, Sindhu, Govind, Murugan Govindakurup, Suresh, Veerankutty, Vishnu, Walsan Kalarikkal & Kumar, Venugopalan Nair Saradamma Anil, 2021, Three new species of Impatiens (Balsaminaceae) from southern Western Ghats, Kerala, PhytoKeys 180, pp. 157-171 : 157

Impatiens shailajae Sindhu Arya & Kumar V.S.A. sp. nov.

Figs 5 , 6 , 7

Type.

India. Kerala, Thiruvananthapuram, Sangili , along the cliffs associated with streams of evergreen forest, 10.0889°N, 77.0595°E, 800 m a.s.l., 20 October 2020, Sindhu Arya & Kumar V.S.A .., 1088 (holotype TBGT!, isotype MH! CAL!) .

Diagnosis.

Impatiens shailajae is similar to I. minae Ratheesh, Anil Kumar & Sivad. but differs with respect to the leaves (broadly ovate thin, rounded apex and green in I. shailajae vs. broadly ovate-orbicular, thick, fleshy, deep pink in I. minae ), spur of the flower (straight and white in I. shailajae vs. slightly curved and pink in I. minae ), lateral united petals (with white transparent papillae and small dorsal appendages in I. shailajae vs. red tipped white papillae and absence of dorsal appendages in I. minae ) and seed (green with long bands of spiral hairs in I. shailajae vs. brown with short hairs in I. minae )

Description.

Scapigerous terrestrial herbs, 10-15 cm high; rootstock faintly tuberous, lithophytic herbs, densely pubescent. Tubers oblate, 4-6 × 2-3 mm. Leaves 2-4, radical, fleshy, 4.5-5.5 × 6.5-7.2 cm, ovate-orbicular or reniform, obtuse or rounded at apex, base cordate, margin crenate or serrate, thickly hairy, dark green above, with a tuft of uniseriate trichomes on upper surface and silky lanuginose hairs on lower surface, nerves pale green, primary veins usually 8, palmate; petioles up to 2.5 cm long, light pink. Scape racemose, straight, 3-4 flowered 8-10 cm long, glabrous. Flowers clustered at the apex, violet, each c. 1.5 cm across; pedicels 1.0-1.5 cm long; bracts thick, broadly ovate, obovoid, 4-5.5 × 2.5-3.2 mm, yellowish with dark purple spots. Lateral sepals 2, each 3.0-4.0 × 2.0-2.2 mm; lower sepals long-spurred, spur slender, 1.0-1.5 cm long, milky white, straight. Dorsal petal broadly orbicular to obovoid, saccate, 5-6 × 5-7 mm, adaxially keeled, glabrous with pubescent keeled part, dull white to yellow or pale purple; keel mucronate, mucro ca. 1 mm long, pale green; lateral united petals 3-lobed, violet, with a slightly curved band of dense white tipped clavate papillae just above base; basal lobes shorter than the distal lobes, ca. 0.5 cm long, broadly oblong, rounded; middle lobes oblong towards tip, 4 mm long, broadly obovate; distal lobes spherical, ca. 6 mm long. Stamens 5, connate, 1.5 × 1.6 mm; filaments white, anthers white. Pollen grains 15 × 19 µm, light pink. Ovary green, 1.7-1.8 × 1.0-1.3 mm, elliptic, broadly acute at apex, glabrous. Capsule glabrous, reddish green, broadly ellipsoid, apex acute, 1.3-1.8 cm long. Seeds 5-8, ca. 1 mm long, surface with tuft of hairs.

Etymology.

Impatiens shailajae is eponymous to Mrs. K.K. Shailaja, former Health Minister of Kerala, honoring her efforts to tackle various epidemic and pandemic situations in the state of Kerala through scientific temper.

Phenology.

August to November.

Distribution and habitat.

The species grows in the unexplored core forest area along steep slippery cliffs, continuously wet by water flow. The species is found to grow along with I. verticillata and Fimbristylis spp. in the near vicinity.

Conservation status.

The species was scattered in 3-4 population with 7-10 individuals per population. The population is well conserved without any disturbance as it was obtained from the interiors of protected forest. However, considering the lesser number of populations distributed across hardly 0.5 km, the species is assessed here as Critically Endangered (CE) by applying the criterion d ( IUCN 2019).

Other notes.

Impatiens shailajae belongs to section Impatiens Tuberosae , characterized by many-flowered racemose inflorescence; capsule clavate or linear, seed ellipsoid or ovoid and lateral sepals 4 with inner 2 fully developed ( Yu et al. 2015). Impatiens shailajae also shares similarity with I. scapiflora but is distinct with respect to the color and shape of papillae on the standard petal, tuberous stolon and trichomes on the leaf. Further, the shape of dorsal petal and its keel is distinct in this new taxon which is easily visible at first glance. All these character combinations along with its undisturbed habitat (localized distribution) and micromorphology (prominent seed hair banding pattern and pollen morphology) further support the status of newly described species.

Specimen examined.

Impatiens shailajae India. Thiruvananthapuram Sangili, 15 October 2020, Arya & Kumar V.S.A. 2011 (MH!, TBGT!). I. scapiflora India. Idukki, 18 August 2019 Arya & Kumar V.S.A. 490 (TBGT!).

Figures

Figure 5. Impatiens shailajae A habit B flower (front view) C flower (lateral view) D lateral petal E dorsal petal F lateral sepal G lower sepal with spur H gynoecium I scape lower surface J scape upper surface K leaf trichomes L papillae on petals M seed. Photos by Arya Sindhu.

Figure 6. Impatiens shailajae A habit B flower C lateral sepal D dorsal petal E lateral petal F stamen G gynoecium. Illustration by V. S. Anilkumar.

Figure 7. Distribution map of Impatiens achudanandanii, Impatiens danii and Impatiens shailajae.