Swertia pahalgamensis Tajamul Islam, Anzar A. Khuroo & Irshad A. Nawchoo, 2022

Islam, Tajamul, Khuroo, Anzar Ahmad & Nawchoo, Irshad A., 2022, Swertia pahalgamensis (Gentianaceae), a new species from Kashmir Himalaya, India, Phytotaxa 547 (2), pp. 201-207 : 203-205

Swertia pahalgamensis Tajamul Islam, Anzar A. Khuroo & Irshad A. Nawchoo , sp. nov. ( Figures 1–3 )

Diagnosis

The described species morphologically resembles with S. thomsonii in few characters such as nature of rhizome, habit, fruit type and stem but differs in having basal leaves 15.5–17.5 cm long, elliptic-spathulate, apices acute (vs. 23–30 cm long, elliptic-oblong, apices sub-acute), base of cauline leaves usually free or rarely connate, up to 0.6 cm (vs. connate, up to 2.5 cm), sepals 8.5–9.5× 3–4 mm, margin serrate on upper part, apices acute (vs. 10–10.5 × 2–3 mm, margin entire, apices acuminate), petals 8.5–10.5 × 5–6 mm, ovate, yellowish green, apices sub-obtuse, fused at base; nectar guides with prominent bluish straight lines (vs. 12–13.5 × 4–5 mm, elliptic, white, apices acute, spreading; nectar guides with inconspicuous straight lines), nectaries 1.1–1.2 × 1.1–1.3 mm, round to cushion-shaped, viscous, sub-confluent, present above the base of petal (vs. 1.4–1.5 × 0.8–0.9 mm, elliptic-oval, non-viscous, confluent, present at the base of petal), fimbriae 5–7 per nectary, 1–2 mm long, sparsely oriented all around the margin of nectary (vs. 14–16 per nectary, 3–5 mm long, profusely oriented all around the margin of nectary), stamens 4.0– 5.5 mm long, anthers 1.5–2 mm long, oblong, apices obtuse (vs. 7–8 mm long, anthers 2–3 mm long, ovate, apices apiculate), capsule 4.5–5.5 mm wide (vs. 2–4 mm wide), seeds 4.0–4.5 × 3.5–4.0 mm, oval-round, wings 1.0– 1.2 mm wide (vs. 3.0–3.5 × 2–2.5 mm, oval-oblong, wings 0.5–0.9 mm wide).

Type:— INDIA. Kashmir , Anantnag district , Royal Sar, Pahalgam, 34.20˚N, 75.22˚E, 3590 m asl, 28 August 2021, Tajamul Islam, Anzar A. Khuroo & Irshad A. Nawchoo 46288 (holotype: KASH!, isotype KASH!) .

Description

Perennial herb, 50–80 cm tall. Rhizomatous with fibrous roots; rhizome 6–8 × 1.5–2.5 cm. Stem erect, simple, hollow, glabrous, cylindrical in outline. Basal leaves 15–25, elliptic-spathulate, petiolate, 15.5–17.5 × 3–3.5 cm, margin entire, apices acute. Cauline leaves, 3–6 pairs, opposite, sessile, free to rarely connate up to 0.6 cm, elliptic to lanceolate, entire, sub-acute, 2–7.5 × 1–2.5 cm, leaf size gradually decreases toward upper-side. Inflorescence paniculate cyme, 25.5–27.5 cm long. Flowers tetramerous, pentamerous or rarely hexamerous, actinomorphic, 20–40 in number, open flower diameter 2.4–2.7 cm, bracteate, pedicels 1.0– 3.8 cm long. Calyx persistent, sepals glabrous, lanceolate, margin serrate on upper part, apices acute, 4–5 in number, 8.5–9.5 × 3–4 mm. Petals yellowish green, ovate, entire, obtuse, 4–5 in number, 8.5–10.5 × 5–6 mm; nectar guides with prominent bluish straight lines; pair of nectaries above base of the petal, sub-confluent, viscous, round to cushion-shaped, 1.1–1.2 × 1.1–1.3 mm; fimbriae 5–7 per nectary, sparsely occur all around the margin of nectary, 1–2 mm long. Stamens 4.0– 5.5 mm long; anthers 1.5–2.0 × 0.6–1.0 mm, bilobed, oblong, sub-dorsifixed, dehiscence longitudinal, apices obtuse. Carpels 2, syncarpous, placentation parietal; ovary superior, lance-shaped, 4.5–5.5× 2–2.5 mm; style reduced; stigma bifid. Fruit capsule with persistent calyx, oblong, 8.5–11.5× 4.5–5.5 mm, septicidal dehiscence. Seeds 55–65 per capsule, oval-round, winged, brownish, flattened, 4.0– 4.5 × 3.5–4.0 mm, wings 1–1.2 mm wide.

Phenology:— Vegetative phase occurs from June–July; flowering from August and extends up to mid-September; fruiting from September–October.

Distribution and Ecology:— Swertia pahalgamensis is currently reported only from the type locality in Royal Sar area of Overa-Aru Wildlife Sanctuary (Pahalgam, Kashmir Himalaya, India). It occurs in the alpine zone at an altitude of 3590 m asl.The species grows on moist slopes of meadows with rocky substrate and along the banks of steep mountain streams. The habitat is dominated by herbaceous plants and the associated species include: Euphorbia wallichii Hooker (1887: 25) , Caltha palustris var. alba ( Cambessedes 1841: 6) Hooker & Thomson (1855: 40) , Trifolium repens Linnaeus (1753: 767) , Sibbaldia cuneata Edgeworth (1846: 44) , Nepeta laevigata (D. Don 1825: 110) Hand. -Mazz. (1936: 916), Artemisia roxburghiana Besser (1836: 57) , Bupleurum candollei Wallich ex Candolle (1830: 131) , Rhodiola himalensis (D. Don 1825: 212) S.H. Fu (1965: 121) .

Etymology:— The specific epithet ‘ pahalgamensis ’ is derived from the area of collection, i.e., Pahalgam (Kashmir Himalaya, India). It is a famous Himalayan tourist spot well-known for its picturesque beauty with temperate coniferous forests, pristine alpine lakes and snow-clad mountains.

Taxonomic Note: This newly described species falls under the genus Swertia based on rotate corolla, shape and nature of nectaries and presence of fimbriae. It closely resembles with S. thomsonii in some characters but differs in many morphological characters ( Figure 3 ). It also shows some morphological resemblance with S. marginata Schrenk (1842: 353) in having similar habit, shape of sepals, a pair of nectaries per corolla lobe and type of fruit as in S. pahalgamensis , but differs in having oblong corolla lobes, nature and cup-shaped nectaries, size of fimbriae and filaments, shape and color of anthers, narrowly ovoid fruit and ellipsoidal seeds (FoC 2008).

Conservation Note: During the present study, about 150 individuals were recorded from the type locality. The new species is so far known only from the type locality, i.e., Royal Sar area of Pahalgam in Kashmir Himalaya, India. In future, more extensive surveys in the study area and neighbouring regions may facilitate empirical evaluation of conservation status for this new species. However, it is relevant to mention that the type locality is used by the pastoralists for livestock grazing and recently huge tourist influx may lead to its habitat degradation, which in near future may endanger the existing natural populations of this newly described species.

Figures

FIGURE 1. A—Location map of Swertia pahalgamensis (Royal Sar, Pahalgam); B—Habit and habitat of S. pahalgamensis; C—Voucher specimen (Holotype); D—Habit and habitat of S. thomsonii; E—Voucher specimen.

FIGURE 2. A—Habit and habitat of Swertia pahalgamensis; B—Rhizome; C—Basal petiolate leaves; D—Flower; E—Sepal (dorsal side); F—Sepal (ventral side); G—Petal (dorsal side); H—Petal with pair of fimbriate nectary (ventral side); I—Nectary with fimbriae; J&K—Stamen with oblong and sub-dorsifixed anther; L—Carpel; M—Capsule; N—Seeds.

FIGURE 3. Comparison of distinguishing characters between Swertia pahalgamensis (A1–A8) and S. thomsonii (B1–B8); A1 & B1— Flower; A2 & B2—Cauline leaves with connation; A3 & B3—Sepal; A4 & B4—Corolla lobe; A5 & B5—Pair of fimbriate nectary on corolla lobe; A6 & B6—Stamens; A7 & B7—Capsule; A8 & B8—Seeds.