Impatiens neo-uncinata, Arya, Sindhu & Kumar, Venugopalan Nair Saradhamma Anil, 2024

Arya, Sindhu & Kumar, Venugopalan Nair Saradhamma Anil, 2024, Impatiens neo-uncinata (Balsaminaceae), a new species from southern Western Ghats of Kerala, India, Phytotaxa 644 (1), pp. 1-9 : 2-6

Impatiens neo-uncinata VSAKumar & Sindhu Arya., sp. nov. ( Figure 1 & 2 )

Type: India, Kerala, Thiruvananthapuram District: Agasthyamala peak, 8°39’52.6452” N; 77°36’16.5743”E, ± 1600m, 16 Aug 2019, Arya & Anilkumar 1222 (holotype: UCBD!; isotype: UCBD!). ( Figs. 1 & 2 ).

Diagnosis: Impatiens neo-uncinata is most similar to I. uncinata Wight (1837:11) in general habit and shapes of leaves but differs with respect to flowers (0.5–0.8 cm white in I. neouncinata vs. 1.4–1.6cm pink-purple in I. uncinata ) basal lobe (triangular, white with red spot vs. circular to deltoid, pink with no spots) distal lobe (dolabriform, white with red spots on the throat vs. oblong obovate pink with spots absent on the throat) dorsal petal (ovate-broadly lanceolate not simulating standards in size and shape vs. broadly ovate simulating standards in size and shape) seed (testaglabrous vs. hairy 2–3 bands) pollen (rod-shaped, apocolpia prominent vs. sub-rectangular-squarish, apocolpia not prominent).

Description (macromorphology):— Herbs, 4–20 cm tall. Stems simple or branched, purple, non-sticky, terete at base, pubescent on younger shoot, lower region glabrous. Leaves simple, opposite decussate; lamina 2.5–4.3 × 1–2 cm, ovate, slightly serrate at margins, often wavy, cordate at base, acute at apex, dark green above, pale green below, with scattered trichomes on upper surface, glabrous below; petioles 1.2–2 cm long, grooved, glabrous. Inflorescences 2–4- flowered raceme; peduncles 2–5 cm long, non-sticky, green brown; pedicels 4–6 mm long, erect, smooth, dark brown; bracts 1–1.4 mm long, lanceolate, green, persistent. Flowers 2.2–2.5 × 0.7–1.2 cm; sepals 2, free; lower sepal saccate, entire at margins, conical at apex, white with reddish patches; spur 2–3 mm long, hooked, green; lateral sepals 1–2 × 1.2–1.3 mm, ovate-lanceolate pointed apex greenish-white, short, not simulating standards in size and shape, entire at margins, glabrous; petals white, delicate; dorsal petal 2.2–2.6 × 1.8–2.1 mm, ovate-lanceolate red spotted throughout, acuminate apex and apex reflexed thin, not foldedwidely, entire at margins, rounded at base and apex; lateral united petals 1.2–1.3 × 0.8–0.9 cm, entire at margins, with a pink spot between the basal and distal lobe; Basal lobe roughly triangular, white specked with red spots, prominent; distal lobe dolabriform or hatcher shaped, white with red spots at throat; stamens 5; filaments 1.8–2 mm long, united, white, papery; anthers 5–6 × 1.3–1.4 mm, united, oval, extrorse, pink, longitudinally dehiscing; pollen 27–29 × 26–28 μm, white, spheroidal, with the exine reticulate; ovary 1.8–2 × 1 mm, elliptic, pale green to reddish; style short; stigma sticky, crested. Capsules 7–9× 2–4 mm, short ovate-fusiform, acute at apex, green, 1–2 seeded. Seeds 1–1.5× 0.5–1 mm, ovate, with the surface glabrous.

Description (micromorphology):— Pollen 3 colpate, cylindrical-rod shaped, 20–21µm × 8–9µm. Bilateral finely reticulate, apocolpia prominent, mesocolpia slightly demarcated. Muri moderately thick ca. 2 µm, duplibaculate, lumina 2.5 µm. Inter luminarbacules present, approximately 2–5 in each, or even absent in few. Seed ovate 3–4 mm × 1–2 mm, apex pointed, epidermal cells irregular, scattered outgrowth which are cylindrical in shape with blunt apex are visible towards the hilum region.

Distribution and habitat:— I. neouncinata is known only from the type locality, at 1000–1250 m of elevation. It grows in open areas of the evergreen forests, particularly on wetlands, with a very limited number of individuals. Each plant spreads over an area of nearly 1–2 m 2.

Phenology:— Flowering and fruiting from August to December.

Etymology:— The specific epithet is a modified name of the closely allied taxon I. uncinata . The new species apparently resembles I. uncinata but has distinct traits for delineation.

Conservation status:— The new species is studied from three subpopulations in a protected area, each separated by a distance of 5 km. The estimated Extent of Occurrence (EOO) is 25 km 2 and the Area of Occupancy (AOO) is less than 10 km 2. The number of mature individuals is estimated to be 100–120, when considering all the localities. Since these locations are inside a protected area, the likelihood of a decline due to anthropogenic activity is negligible. Nevertheless, we recommend that the species be categorized as Endangered [EN] based on criterion D: population size estimated to number less than 250 mature individuals ( IUCN, 2020).

Additional specimens examined. INDIA. Kerala: Thiruvananthapuram district:Agasthyamala biosphere reserve, Athirumala 8 ◦ 9713” N 77.3 ◦ E, ± 1600 m, 15 July 2020 Govind & Anilkumar 675 (UCBD!).

Impatiens uncinata : INDIA. Kerala: Thiruvananthapuram district: Agasthyamala biosphere reserve, Athirumala 8 ◦ 9713” N 77.3 ◦ E, ± 1600 m, 15 July 2020 Govind & Anilkumar 681 (UCBD!).

Impatiens cordata : INDIA. Kerala: Idukki district: Cheruthoni 9 ◦ 8612” N 76.9600 ◦ E, ± 800 m 20 September 2022 Arya S & Anilkumar 1026 (UCBD!).

Notes:— Impatiens is a diverse genus and it usually prefers a species specific micro habitat. Studies on the genus reveal that its diversity is different and unique for different geographical locations. In India, the highest diversity of Impatiens in found in the Himalayan and north eastern regions having distinctly different species distributions. Southern Western Ghats accounts for the second largest diversity of the genus. Yu et al.(2015) gave a worldwide classification of Impatiens into two subgenera and sections. Impatiens neo-uncinata is assigned to section Scorpioidae of subgenus Impatiens due to its decussate leaves, 2–4-flowered inflorescence and short fusiform capsules. Impatiens found in southern Western Ghats of India has been studied and documented by Bhaskar (2012). Considering the studies by Bhaskar (2012), Impatiens neouncinata belongs to the section subumbellata which includes 18 species and is characterized by flower in umbellate or subumbellate inflorescence or in contracted raceme terminating in a long axillary peduncle; plants herbs or shrub; leaves opposite or alternate, standard keel petal with or without dorsal auricle and seeds brownish, hairy. A key to delineate the 19 species belonging to the section subumbellata ( Bhaskar 2012) is given below: Characters of unexamined specimens has been taken from ( Bhaskar 2012) for the preparation of key.

Figures

FIGURE. 1. Impatiens neo-uncinata. A. Habit; B. Flower, frontal view; C. Flower, lateral view; D. Lateral sepals; E. Lower lobe; F. Dorsal petal; G. Lateral united petals; H. Lower sepal with spur; I. Stamens; J. Gynoecium; K. Mature fruit; L. Seeds.

FIGURE. 2. Impatiens neo-uncinata. A. Habit; B. Flower, frontal view; C. Flower, lateral view; D. Lateral sepals; E. Lowerlobe; F. Dorsal petal;G. Lateral united petals; H. Lower sepal with spur; I. Stamens; J. Gynoecium; K. Mature fruit; L. Seeds;(A–L from the holotype; illustrated by V.S.A.Kumar).