Impatiens danii M.G. Govind, Sindhu Arya, V. Suresh & 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 danii M.G. Govind, Sindhu Arya, V. Suresh & Kumar V.S.A. sp. nov.

Figs 3 , 4 , 7

Type.

India. Kerala, Idukki, Munnar , along the streams of highland 10.0889°N, 77.0595°E, 800 m a.s.l., 16 October 2019, M.G. Govind & Kumar V.S.A .., 1078 (holotype TBGT!, isotype MH! CAL!) .

Diagnosis.

Impatiens danii is similar to Impatiens goughii Wt. (1831:160) but different in terms of color of flower (white with yellow blotch on the throat in I. danii vs. purple with white blotch on the throat in I. goughii ), nature of peduncle and pedicel (non- sticky, smooth 3-3.5 cm in I. danii vs. sticky, viscous 7-8 cm in I. goughii ), bracts (absent in I. danii vs. present and minute in I. goughii ), shape of spur (curved and equal or longer than flower in I. danii vs. straight and shorter than flower in I. goughii ), shape of dorsal auricle (short, lanceolate and equals the length of wings in I. danii vs. long and filiform and half the length of wings in I. goughii ), capsule (ovate in I. danii vs. ellipsoidal in I. goughii ) and shape of seed (ellipsoidal with bands of hairs in I. danii vs. ovoid with short hairs in I. goughii ).

Description.

Annual, erect herb, 10-20 cm high; stem simple to moderately branched, glabrous, often slightly pubescent terete, with few scattered, brown, sessile or stipitate glands, particularly in the lower part of the stem. Lower and middle leaves opposite, petiolate to subsessile; petiole up to 1.5 cm long; lamina ovate to ovoid or elliptic-lanceolate, 3.5-8.5 × 1-1.5 cm, base rounded with auricled lobes, apex acuminate, margins crenate, dentate to serrate or serrulate (usually in upper leaves) with cuspidate teeth; surfaces glabrous; upper leaves alternate, sessile, oblong-lanceolate, smaller than lower leaves, apex acuminate, surfaces glabrous or sometimes with few glands, particularly on lower surface. Inflorescence peduncled, 8-12 flowered racemes arising from the axis of alternate leaves in the upper part of the stem; peduncle up to 5 cm long, glabrous, with small brown spots; bracteoles absent; pedicels slender, 1-1.5 × 0.6-0.9 cm, glabrous, with or without sparse brown spots. Flowers 1-1.2 × 0.6-0.8 cm, white; with yellow-purple blotch at throat. Lateral sepals 2, opposite, one on either side, ovate to lanceolate, 1.3-1.8 × 0.6-0.8 mm, base cordate, unequally parted, margins entire, apex acute, surfaces glabrous with conspicuous purple dots. Dorsal petal orbicular to oblong, 2-3 × 1.5-2 mm, apex slightly notched, margins entire or wavy, concave in the middle with spreading sides, slightly keeled on dorsal side, 0.5-0.8 cm long. Lateral petals 2 lobed, lobes unequal with second lobe long and ovate, each lateral petal equal ca. 1-1.2 × 1.0-1.2 cm, margins (outer and inner) entire or wavy. Lower sepal saccate, white with curved spur. Spur equals the length of the lateral petal. Stamens 2-2.5 mm; filaments 1-1.5 mm long, anthers 0.8-1.5 mm long, partly fused; pollen grains bilateral 12 × 14 µm milky white. Ovary oblong-elliptic, 2-3 mm long, glabrous; style 0.1-0.4 mm long. Capsules ovoid, 1-2.8 cm long, 0.2-0.5 mm broad, glabrous, green with purplish base and apex, 4-10 seeded; seeds green, oblong or sub ovoid, 2-3.6 × 1.5-2 mm, surface covered with hairs.

Etymology.

The specific epithet ' Impatiens danii ' is given in honor of Dr. Mathew Dan, Senior Scientist and Head, Plant Genetic Resource Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Thiruvananthapuram, Kerala, as a recognition of his immense contributions in the field of systematics and conservation of angiosperms in the Western Ghats.

Phenology.

August to November

Distribution and habitat.

Impatiens danii is found to grow along the mud cliffs. Other taxa like I. herbicola , I. munnarensis and Selaginella ciliaris have been observed to grow along with this species.

Conservation status.

Impatiens danii is known from a single location only (for a total of 50 individuals), and the AOO (Area of Occupancy) is 2 km2. On the basis of the IUCN Red List criteria ( IUCN 2019) and the available data, we can apply the criteria B2 and C2ai and assess I. danii as Critically Endangered (CR).

Other notes.

Impatiens danii belongs to the section Impatiens Uniflorae , characterized by capsules that are short-fusiform, conspicuously turgid at middle, ca. 1 cm long, inflorescence a raceme with 2(-5) flowers and seed ellipsoid. Further the color of flower, blotches on throat, seed surface and shape of spur are distinct characters that delineate I. danii from other reported species.

Specimen examined.

Impatiens danii India. Munnar, Idukki. 6 July 2020, M.G. Govind 987 (TBGT!). I. goughii India. Munnar, Idukki. 6 July 2020, M.G. Govind 988 (MH!).

Figures

Figure 3. Impatiens danii A habit B flower (lateral view) C flower (front view) D dorsal petal E lateral sepal F, G lateral united petals H stamen I gynoecium J fruit. Photos by Govind.

Figure 4. Impatiens danii A habit B flower C stamen D dorsal petal E basal lobe F lateral sepal G lateral united petals (distal lobe) H gynoecium I lower sepal with spur J fruit. Illustration by V. S. Anilkumar.

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