Polycarpaea palakkadensis, Arya, Sindhu, Kumar, Venugopalan Nair Saradamma Anil, Nathanpillai, Ambika Viswa, Philip, Alen Alex, Sojan, Jose & Suresh, Veerankutty, 2021

Arya, Sindhu, Kumar, Venugopalan Nair Saradamma Anil, Nathanpillai, Ambika Viswa, Philip, Alen Alex, Sojan, Jose & Suresh, Veerankutty, 2021, Polycarpaea palakkadensis (Caryophyllaceae), a new species from Kerala, South- West India, Phytotaxa 527 (2), pp. 151-157 : 154-156

Polycarpaea palakkadensis V.S.A Kumar, S.Arya & Suresh sp. nov. ( Fig 1a ).

Type: — INDIA. Kerala: Palakkad district, Malampuzha , 160 m, 10°50’07.7”N 76°40’44.5”E, 20 th October 2019, Suresh & Arya 564 (holotype UCBD !, isotype UCBD !).

Diagnosis: — Polycarpaea palakkadensis is morphologically similar to Polycarpaea rangaiahiana Geethakumari et al. (2015: 182) sharing reddish stem nodes that are villous but it differs with respect to arrangement of leaves (verticillate in P. palakkadensis vs. pseudoverticillate in P. rangaiahiana ), shape and length of stipules (linear-lanceolate with acute apex and 1 mm long vs. ovate lanceolate with acuminate apex and 4 mm long), shape of bract (linear-lanceolate fused in pairs vs. ovate lanceolate not fused in pair, free), bracteoles (pappus or thread-like vs. ovate-lanceolate), shape and colour of sepals (ovate-obovate, acute at apex, white with red spot on the base vs. ovate lanceolate, acuminate apex, bright orange), shape, length, and colour of petals (ovate, 0.3 mm long, mucronate at apex, dark-brown vs. elliptical, 0.8–1.0 mm long, acute at apex, dark-red), length of stamen (filament 0.1 mm long, shorter than the anthers vs. filament 0.5 mm long as long as the anthers), shape of ovary (oblate spheroidal vs. prolate), shape of capsule (spheroidal-ellipsoidal, style not persistent, tips curved vs. ovoid, style persistent, tips not curved), and number, colour, and shape of seeds [1(–2), whitish yellow, ovate with no striations vs. 3–5, brown, subreniform with striations)

Description: —Annual herbs, erect or suberect, branched at base, ca. 7.5 cm high. Stem terete or angular, densely villous, nodes reddish swollen, internodes ca. 2 cm long. Leaves verticillate, sessile, linear, green, 1.0– 2.5 cm long, base cordate, margin wavy, apex acute, surface glabrous, blade 1-veined, prominent on abaxial side; stipules scarious, linear-lanceolate, associated with narrow filamentous structures (1.2–2.0 × ca. 0.5 mm), margin entire, acute not nerved, yellowish at the base, white above. Inflorescence in terminal branched cyme, ca. 1.5 cm long; bracts paired, fused at base, linear-lanceolate, entire along the margin, acuminate, white, ca. 1 mm long. Flowers 1.1–2.4 mm long; bracteoles capillaceous and holding the bracts in position, 1–1.5 mm; pedicels 1.5–1.8 mm long, green villous. Sepals 5, fused at base, ovate-oblong (1.1–1.2 × ca. 0.9 mm), entire at the margin, acute at apex, white with a red spot on base, base mucronate, midrib prominent. Petals 5, ovate-oblong often cordate (0.4–0.6 × 0.3–0.5 mm), margin entire, oblong to round at apex, enclosing the ovary, 1/3–1/2 as short as sepals, dark red. Stamens 5, forming a ring with petals and encircling the ovary, ca. 0.1 mm long; anthers yellow, oblong, basifixed. Ovary 1-loculed, shortly stipitate, oblate spheroidal, 0.2–0.4 × 0.2–0.3 mm, glabrous, placentation free central; style 0.10–0.15 mm, shorter than the ovary, slender; stigma capitate. Capsule spheroidal (1.2–1.5 × ca. 0.4 mm), shortly stipitate, 4-valved, breaks along the suture, brownish, scarious along margin. Seeds (1–)2, ovoid (0.1–0.2 × 0.1–0.2 mm), white-yellow with no striations.

Phenology:— Flowering and fruiting times July–October.

Habitat and distribution:— Polycarpaea palakkadensis grows on the hillock terrains in Palakkad district (Kerala granite outcrop in the northern side of Palakkad gap, the largest break in western Ghats having an arid climate with seasonal fires). One of the common species that emerges after the initial rains is members of the genus Polycarpaea , especially P. aurea ( Wight 1850: 44) Dunn (1915: 65) . P. palakkadensis is also seen in a similar habitat. The associated taxa include Indigofera linnaei Ali (1958 ; 549) and I. uniflora Buchanan-Hamilton ex Roxburgh (1814: 57) .

Conservation status:— Since Polycarpaea palakkadensis could occur in further sites in SW-India (and India as a whole), we think that further data are required to ascertain the conservation status of the new taxon. As a consequence, the new species is here assessed as DD (Data Deficient) according to the IUCN criteria ( IUCN 2021).

Taxonomic notes:— The proposed new species is closely allied to Polycarpaea rangaiahiana , occurring in Kannur district (Kerala), but it is distinct with respect to the floral traits ( Table 1 ). In Kerala, P. corymbosa (Linneaus 1753: 205) Lamarck (1797: 129) has a wide distribution and P. palakkadensis resembles P. corymbosa with respect to verticillate, linear leaves and dense cyme, but differs with respect to shape of stipules (ovate lanceolate, 2–4 mm in P. corymbosa vs. linear lanceolate, 1.2–2.0 mm in P. palakkadensis ), sepals (hyaline, lanceolate, free vs. nonhyaline ovate-oblong, fused at base), petals (broadly ovate, whitish-reddish vs. ovate oblong or cordate, dark brown-dark red), bracteole (lanceolate vs. capillaceous), ovary (ovate vs. oblate-spheroidal), capsule (3-valved, ovoid vs. 4-valved, spheroidal), and seeds (5–15 flat with prominent reticulate surface ornamentation vs. 1–2 ovoid with smooth surface). The new species also resembles P. aurea with respect to brown colour of the petals but it differs by various characters, as reported in Table 1 . A key to demarcate the new species from the other six species found in India is given below.

1. Leaves basal and cauline, flowers in spike, capsule thin walled.......................................................................................... P. spicata

1. Leaves only cauline, flowers in dense or lax cyme, capsule thick walled .........................................................................................2

2 Petal pinkish-purple, plant glabrous...................................................................................................................................... P. diffusa

2 Petals pinkish-yellow, plant densely tomentose .................................................................................................................................3

3 Stem with greyish hairs, petal lightly coloured, leaves set with green slender node ..................................................... P. corymbosa

3 Stem with white hairs, petal brightly colored, leaves set with reddish swollen node ........................................................................4

4 Plants not stunted, sepals bright white-reddish, petals yellow-brown................................................................................................5

4 Plants stunted, sepals hyaline, petals violet.............................................................................................................. P. majumdariana

5 Leaves opposite-decussate, anthers white-cream, stamen 1/2 as long as the petal ................................................................. P. aurea

5 Leaves pseudoverticillate at red villous nodes, anthers bright-yellow stamen 1/4 as long as the petal.............................................6

6 Sepals ovate-oblong, petals ovate-cordate, with apex rounded, gynoecium oblate-spheroidal, capsule 1–2 seeded, each seed ovoid.......................................................................................................................................................................... P. palakkadensis

6 Sepals lanceolate, petals ovate-lanceolate, apex acute, gynoecium prolate, capsule 3–10-seeded, each seed sub-reniform............... ................................................................................................................................................................................... P. rangaiahiana

Additional specimens examined (Paratypes):— Polycarpaea palakkadensis . INDIA: Kerala: Palakkad District, Malampuzha, Navodaya , 115 m, 10°49’37.9”N 76°40’29.8”E, 26 September 2021, Suresh & Alen 1055 ( UCBD) , Rock Garden Premise, 120 m, 10°49’30.9”N 76°41’15.5”E, 26 September 2021, Suresh & Arya 1056 ( UCBD) , Anakkal Road , 120 m, 10°49’20.7”N 76°41’59.0”E, 27 September 2021, Suresh & Ambika 1058 ( UCBD) .

Figures

FIGURE 1. Polycarpaea palakkadensis a. habit; b. inflorescence; c. stipules; d. bract; e. flower f. & g. sepals; h. petal; i. stamen; j. gynoecium; k. fruit; l. seed (pictures by A. Sindhu).

Tables

TABLE 1. Morphological comparison between Polycarpaea palakkadensis and the similar species P. aurea and P. rangaiahiana.

	P. palakkadensis	P. rangaiahiana	P. aurea
Leaves	Pseudoverticillate	Pseudoverticillate	Opposite-decussate
Stipules	Linear-lanceolate, entire margin, 1 mm, short acute, creamy white, not nerved	Ovate-lanceolate, fimbriate along margin, 4 mm, long-acuminate, reddish at the base, white above, prominently nerved	Lanceolate, entire at margins, acuminate at apex, ca. 3 mm long, colourless or yellowish-brown, slightly silvery, not nerved
Inflorescence	Irregular, dense cyme	Regular (cymes), dense	Regular lax cymes
Bract	Ovate-oblong entire margin, fused at the base, creamy white	Ovate-lanceolate, fimbriate along the margin, not fused at base, white	Ovate-lanceolate, entire at margins, not fused at base, grey with a faint brownish tinge
Bracteole	Capillaceous, not prominent	Ovate-lanceolate prominent	Ovate-lanceolate, prominent
Sepal	Ovate-oblong, entire margin, acute or blunt apex, white	Ovate-lanceolate, entire at the margin, acuminate at apex, bright orange.	Ovate-lanceolate, acute-acuminate at apex, scarious, bright orange-reddish.
Petal	Ovate-cordate, fimbriate margin, round to mucronate at apex, dark brown	Elliptic, margin entire, acute at apex, dark-red	Oblong-obovate, margin entire, obtuse at apex, yellowish-brown
Stamens	0.1 mm, filament very short	0.5 mm, filament as long as anther	1 mm, filament as long as anther
Gynoecium	Oblate spheroid	prolate	conical
Capsule	Style not persistent, smooth, tips not recurved after dehiscence, 1 or rarely 2 seeded	Style persistent, finely lined, tips not recurved after dehiscence, 3–10 seeded	Style persistent smooth, shining, glabrous, tips recurved after dehiscence, 5-many seeded
Seed	1–2 Ovoid-elliptical creamy white	(6–)10, sub-reniform brown	3–5, reniform brown