Swertia jayantii Amber Srivastava & JS Khuraijam

Srivastava, Amber & Khuraijam, Jibankumar Singh, 2024, Swertia jayantii (Gentianaceae): a new species from North-East India, Phytotaxa 640 (1), pp. 57-64 : 58-61

Swertia jayantii Amber Srivastava & JS Khuraijam sp. nov. ( Figs. 1 & 2 )

Type:— INDIA, Meghalaya, Jaintia hills, Nartiang , 25°34’03”N 92°12’52”E, 1200 m, 15 October 2022, Amber Srivastava 349334 (holotype: LWG; isotype: BSD) .

Diagnosis:— Swertia jayantii shows close resemblance with Swertia cordata Wall. in having a single naked nectary, narrowly winged quadrangular stem and bluish-veined corolla lobes. However, S. jayantii can be clearly differentiated from S. cordata in having deltoid nectar 1.2–1.4 mm (vs. rounded or ovoid nectar 1.5–1.9 mm), leaf base obtuse (vs. leaf base cordate), corolla lobes incurved (vs. corolla lobes flat) and calyx shorter than corolla (vs. calyx equal or longer than corolla).

Swertia jayantii has long been confused as Swertia cordata due to similarity in few morphological characteristics and not observing the nectary characteristic which is not quite prominent in dried specimens.

Description:— Annual, erect, solitary or branched herbs, 10–50 cm high. Roots woody, creamish-yellow or pale white. Stem tufted, green or reddish purple, quadrangular, narrowly winged at angles. Radical leaves withered at anthesis. Cauline leaves sessile or sub-sessile, opposite, oblong-lanceolate or ovate-lanceolate 1.5–3.5 × 0.7–2.5 cm, 3–5 veined, obtuse at base, acute at apex, glabrous, margin entire, veins distinct abaxially prominent, green or sometimes purplish black. Inflorescence paniculate thyrse, dense, 10–25cm long, many flowered, axis spreading. Flowers pentamerous, 1.8–2.2 cm across; pedicel 0.4–1.2 cm long, quadrangular or sub-quadrangular; Corolla lobes elliptic-lanceolate, 0.8– 1.2× 0.3–0.5 cm, white with bluish-purple veins, margins slightly involute, apex acute. Nectaries 1 per corolla lobe, slightly raised, naked gland patch, 1.2–1.4 mm, deltoid, present above the base of corolla lobe. Calyx lobes unequal, 1/2 to 2/3 of corolla, narrowly ovate to ovate-lanceolate, apex acute, margins slightly revolute, veins 3, tube 1–2 mm; lobes 5.5–9.0× 1.5–3.5 mm. Stamens 5, 5.4–5.6 mm long, adnate to corolla tube; filaments free, linear to subulate, 5.3–5.5 mm, white, glabrous; anthers ellipsoid, 1.2–1.5 mm long, dark purple. Style short, 0.3–0.5 mm; stigma lobes suborbicular. Capsules 6–8 mm long, ovoid-ellipsoid. Seeds 0.3–0.5 mm in diam., ellipsoid to globose, brown; seed coats longitudinally and thinly corrugate.

Etymology: — The new species is named after Goddess Jayanti (the presiding deity of Jayanti Shaktipeeth) in Nartiang, Jaintia hills.

Flowering and Fruiting: — October–January.

Distribution and Ecology: — Swertia jayantii is found growing on open grasslands or hill slopes of Nartiang hills. It is also found growing luxuriantly on grassy slopes of Mawphlang sacred groove and shaded, moist slopes along forest edges at Smit in Meghalaya ( Fig. 3 ). In most of the localities, it is found growing in association with Swertia macrosperma (C.B. Clarke 1874: 448) C.B.Clarke (1883: 123) , Drosera peltata Thunberg (1797: 7) , Lobelia pyramidalis Wallich (1820: 376) , Osbeckia stellata Buchanan-Hamilton ex D. Don (1822: 674) are commonly occurring species of the region.

Additional specimens examined (Paratypes):— INDIA. Meghalaya: K. & J. hills , Peak forest , 9.11.1938, R. N. De 16632 ( ASSAM!) ; K. & J. hills , Sohra raim ( Sohrarim ), 22.11.1938, S. R. Sharma 17863 ( ASSAM!) ; Shillong, Elephant falls , 22.10.1956, G. Panigrahi 3761 ( ASSAM!) ; East Khasi hills, Mawphlang sacred grove, 25°26’54.99”N 91°45’15.55”E, 1882 m, 16.10.2022, Amber Srivastava 349335 ( BSD!) ; East Khasi hills, Smit , 25°30’58.73”N 91°54’45.30”E, 1790 m, 16.10.2022, Amber Srivastava 349336 ( BSD!) .

Conservation status: — During the field survey in October 2022 and January 2023, more than 500 individuals of S. jayantii were observed in both Khasi and Jaintia hills. A detailed observation of herbarium specimens deposited at ASSAM revealed that most of the collections marked as Swertia cordata from Meghalaya are actually Swertia jayantii . Though S. jayantii is having good population size but is having restricted distribution in India and is also highly exploited for medicinal use by local people by the name of ‘ Chireta’. Due to the limited data available on the exact distribution of the species, it is treated here as ‘Data Deficient’. Considering the present overexploitation of the species for traditional uses, further exploration is required to assess the extent of threats and actual distribution of the species.

Taxonomic Note: — Swertia subgenus Ophelia sect. Ophelia ser. Maculatae comprises species having 1 or 2 naked gland shaped nectaries and is represented by only six species globally. In India, the section is represented by only two species, namely S. cordata and S. bimaculata which are found mainly in temperate regions and foothills.

The newly discovered species, Swertia jayantii , shares similarities with S. cordata , such as its growth habit, pentamerous corolla displaying blue-violet veins, quadrangular stem with narrow wings, and presence of single nectary near the base of corolla. However, S. jayantii distinguishes itself by its deltoid-shaped nectaries, calyx lobes smaller than the corolla lobes, slightly incurved corolla lobes and leaves lacking a cordate base (see Table 1 and Figure 4 for visual representation).

Figures

FIGURE 1. Swertia jayantii sp. nov. A. Habit, B. Flower (front view), C. Flower (side view), D. Corolla showing nectary, E. Calyx lobes, F. Pistil, G. Stamens, H. Variation in leaf shape, I. Seeds. (Prepared by Amber Srivastava).

FIGURE 2. Holotype of Swertia jayantii sp. nov.

FIGURE 3. Map showing distribution of Swertia jayantii in India.

FIGURE 4. Comparison between characters of Swertia jayantii (a1–e1) and Swertia cordata (a2–e2): a1,2. Single flower; b1,2. Petal shape; c1,2. Nectary; d1,2. Calyx; e1,2. Leaf. (Prepared by Amber Srivastava).