Impatiens minnamparaensis Sindhu Arya, Ambika, Alen Alex, V.Suresh, Sojan & V.S.A.Kumar.

Sindhu, Arya, Anilkumar, Venugopalan Nair Saradhamma, Pilllai, Ambika Viswanathan, Philip, Alen Alex, Sojan, Jose & Suresh, Veerankutty, 2024, A new species of Impatiens from the Nelliyampathy region of southern Western Ghats, India, Phytotaxa 650 (1), pp. 83-92 : 84-90

Impatiens minnamparaensis Sindhu Arya, Ambika, Alen Alex, V.Suresh, Sojan & V.S.A.Kumar. , sp. nov.

( Figure 1 & 2 )

Type: India, Kerala, Palakkad District: Minnampara , 10°31’44.7” N; 76°43’11.5743”E, ± 600m, 4 Dec 2021, Arya, Suresh, Sojan & Anilkumar 1198 (holotype: UCBD; isotype: UCBD).

Diagnosis: Impatiens minnamparaensis is most similar to I. sasidharanii in absence of dorsal auricle and spur structure but differs in having leaves (ovate-oblong in I. minnamparaensis vs. linear-lanceolate in I. sasidharanii ), flowers (milky white to pinkish white with a prominent blotch at the throat vs. dull white, yellow or bluish tinged white with no spots at the throat), distal lobe (dolabriform or hatchet shaped, milky white vs. orbicular or obovate, rounded at apex, dull white to yellow or pale pink), basal lobe (conical, white vs. ovate, obtuse to acute at apex, dull white to yellow or pale pink) lower sepal (saccate, dull white with pale pink tip and red stripes vs. boat shaped, pink without any stripes), dorsal petal (ovate-ovoid, beak at the base prominent, white to pink; keel absent or often faintly present vs. broadly ovate, beak at the base not prominent or absent, dull white to yellow to pink, keel mucronate), lateral sepal (linear-falcate, pinkish white vs. linear-lanceolate, glabrous, pale green, pale yellow or purple) and pollen (4 colpate cushion shaped vs. 3 colpate spherical).

The new species also resembles I. rupicola in terms of shape of leaf and habit but differs with respect to pedicel (3–4 cm long with fine puberulous two line in flower and fruit in I. rupicola vs. 1–2 cm long, glabrous in I. minnamparaensis ) dorsal auricle (present vs. absent) and pollen (rod shaped vs. cushion shaped).

Description (macromorphology):—Herbs, 4–10 cm tall. Stems simple branched, purple, non-sticky, terete at base, pubescent on younger shoot, older part glabrous, internodes 1.5–2 cm long, extrafloral nectaries absent, glabrous. Leaves simple, opposite decussate; lamina 1.5–2.3 × 1–1.5 cm, ovate-oblong, slightly serrate at margins, often wavy, cordate at base, acute at apex, dark green above, pale green below, with scattered uniseriate moniliform trichomes on upper surface, glabrous lower surface; petioles 0.5–0.7 cm long, grooved, glabrous, inconspicuous in the younger leaves Flowers 1 per axil, rarely 2, 8–15 × 6–8 mm, milky white to pinkish white; pedicel 1–2 cm long, glabrous, purple; lateral sepal 2.5–3 × 0.5 mm, linear-falcate, pinkish white; dorsal petal 1.5–2 × 1.5–2 mm, ovate-ovoid, beak at the base prominent, white to pink; keel absent or often faintly present; lateral united petals 7–9 × 2.5–3 mm, 2 lobed; basal lobe 2–2.5 × 1.5–2.5 mm, conical, obtuse to round at apex, white; distal lobe 2.5 × 4.5 mm, dolabriform or hatchet shaped, rounded at apex without dorsal auricle, milky white; lower sepal 3.5–4 × 1.5–3 mm, saccate with beaked apex, glabrous, dull white with pale pink tip with prominent red blotch at the throat, tip curved; spur 0.2–0.3 mm long, cylindrical, stout, curved, glabrous, yellow-green. Stamens 5; filaments 1.1–1.2 mm long, united, purple, papery; anthers united, oval, extrorse, yellow, longitudinally dehiscing. Pistil 1.5–2.0 × 0.5–1 mm; ovary oblate. Capsule 1–1.2 cm long, ellipsoid or ovate, glabrous; seeds, ca. 1 mm, 1–2 per capsule, ellipsoidal, glabrous, shining, brownish-black.

Description (micromorphology):—Pollen 4 colpate, 17.5µm × 17.9µm. Surface pattern roughly reticulate forming a non angular apocolpia which is prominent. Mesocolpia is faintly distinguished. Muri measures ca 1 µm, baculate, lumina ca 1.7 µm. intra and inter-luminar bacules are present, 6–10 in each, often free or even fused.

Distribution and habitat:—Known only from Minnampara, Nelliyampathy, Palakkad district in Kerala, where it grows on open grasslands.

Phenology:—Flowering and fruiting from August to December.

Etymology:—The specific epithet Impatiens minnamparaensis corresponds to the type locality Minnampara, which a biodiversity rich spot in the Nelliyampathy hills.

Conservation status:—The new species is studied from two subpopulations in a protected area, each separated by a distance of 500 m. The estimated Extent of Occurrence (EOO) is 5 km 2 and the Area of Occupancy (AOO) is less than 8 km 2. The number of mature individuals is estimated to 30–40, when considering all the localities. Even though the area is under protected forest area, stamping by wild animals and intrusion of visitors by jeep travel forms a threat. 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, 2012). The population had been studied for 3 seasons in the area and there is a population decline percentage of 8 % in the population of I. minnamparaensis from Nelliyampathy hills.

Additional specimens examined. INDIA. Kerala:— Palakkad district: Nelliyampathy, Minnampara 10°31’44.7” N; 76°43’11.5743”E ± 600 m, 29 November 2021 Sojan & Suresh 1200 (UCBD); 20 October 2022 Arya & Alen 2311 (UCBD).

I. rupicola INDIA. Kerala: Palakkad district: Nelliyampathy, Minnampara 10°31’44.7” N; 76°43’11.5743”E, ± 600 m, 29 November 2021 Sojan & Suresh 1222 (UCBD); 20 October 2022 Arya & Alen 2313 ( UCBD); Idukki district: Cheruthoni , 9 ◦ 8613” N 76.96 ◦ E 30 August 2022 Arya 1671 ( UCBD) .

I. sasidharanii INDIA. Kerala: Palakkad district: Nelliyampathy, Minnampara 10°31’44.7” N; 76°43’11.5743”E, ± 600 m, 29 November 2021 Sojan & Suresh 1225 (UCBD); 20 October 2022 Arya & Alen 2315 (UCBD).

Taxonomic notes: — I. minnamparaensis grows in the open muddy grasslands in the interior of Nelliyampathy hills. The habitat is similar to the other Impatiens spp found in this area. Yu et al. (2015) gave a worldwide classification of Impatiens into two subgenera subgen. Clavicarpa Warb. and subgen. Impatiens . Impatiens minnamparaensis belongs to the section Uniflorae under subgenus Impatiens characterized by capsule that are short-fusiform, turgid at middle conspicuously, ca. 1 cm long inflorescence a raceme with 1 (–2) flowers and seed ellipsoid. According to the classification by Bhaskar 2015, I. minnamparaensis belongs to the section Annuae characterized by opposite and decussate leaves and black colored seeds. I. minnamparaensis also shares similarity with I. kodachadriensis Bhaskar & Sringesh (2012:150) in terms of milky white corolla but differs with respect to shape of distal lobe (elliptical vs. hatchet shaped) shape of basal lobe (elliptical vs. ovate) and spur morphology. The new species also resembles I. oppositifolia Linnaeus (1753: 937) in terms of opposite leaves but differs with respect to the shape of leaves (linear-lanceolate vs. ovate oblong), shape of lower sepal (conical vs. saccate) and color of anther (white vs. purple). Key to the closely allied species belonging to this section from Western Ghats is given below:

Key to the species

1a. Stem quadrangular..............................................................................................................................................................................2

1b. Stem not quadrangular........................................................................................................................................................................3

2a. No spots at corolla throat........................................................................................................................................ I. kodachadriensis

2b. Yellow spot at corolla throat.................................................................................................................................. I. eravikulamensis

3a. Lower sepal glabrous conical and anthers white......................................................................................................... I. oppositifolia 3b. Lower sepal pubescent saccate and anthers lilac or pink .................................................................................................................. 4

4a. Spur incurved into a hook yellow-pink ........................................................................................................................... I. tomentosa

4b. Spur straight or slightly curved ..........................................................................................................................................................5

5a. Flowers light pink to deep pink with dark purple or blue or yellow spot on the throat, spur minute, slightly curved ......................6

5b. Flowers pink with no spot on the throat; spur slightly yellow to green ....................................................................... I. sasidharanii

6a. Leaves ovate cordate pubescent basal lobe conical white, lower sepal saccate, pollen 4 colpate ....................... I. minnamparaensis

6b. Leaves obovate oblong or linear; basal lobe ovate purple; lower sepal dolabriform, pollen 3 colpate .............................. I. rupicola

Figures

FIGURE 1. Impatiens minnamparaensis. A. Habit;B. Flowering twig; C.Nectaries on nodes;D. Flower;E. Flower (front view); F. Dorsal petal;G. Lateral sepal; H. Standarad keel petal;I. lower sepal;J. Spot on lower sepal;K. Stamen; L. Gynoecium; M. Seed.

FIGURE 2. Impatiens minnamparaensis (illustration).A. Habit; B. Nectaries on nodes; C. Flower (side view); D. Dorsal petal; E. Lateral sepal; F. Standard keel petal; G. & I. Lower sepal; H. Flower (front view); J. Stamen; K. Gynoecium; L. Seed.