Polycarpaea barbellata V.S.A. Kumar, S. Arya, V. Suresh & Alen Alex, 2022

Arya, Sindhu, Kumar, Venugopalan Nair Saradamma Anil, Pillai, Ambika Viswanathan, Alen, Alex Philip, Sojan, Jose & Suresh, Veerankutty, 2022, Three new species of Polycarpaea (Caryophyllaceae) from Kerala, South India, PhytoKeys 213, pp. 95-110 : 95

Polycarpaea barbellata V.S.A. Kumar, S. Arya, V. Suresh & Alen Alex sp. nov.

Figs 5 , 6

Type.

India. Kerala, Palakkad district, Kuthanur, Chedukamala 10°41'42.6"N, 76°31'06.3"E, 150 m a.s.l., 20 October 2021, V.S.A Kumar, Suresh V & Arya S., 3010 (holotype UCBD! isotype UCBD!) .

Diagnosis.

Polycarpaea barbellata is morphologically similar to Polycarpaea aurea with respect to yellow-orange color of sepals but differs with respect to stipules (oblong, parted into 3 with a long acicular structure in the center and other two parts barbellate vs. lanceolate parted into 2, free, with no central structure), Inflorescence (dense cyme vs. lax cyme), bract (linear, white, acicular apex vs. lanceolate-ovate, greyish-brown, acuminate apex), bracteoles (Capillaceous with acicular apex vs. ovate lanceolate with acute apex), petals (wedge shaped, whitish-lilac vs. broadly ovate-oblong, yellowish-brown), Gynoecium (spheroidal, yellowish green reduced vs. conical, short yellow), capsule (style not persistent, tip not recurved, 2-3 seeded vs. style persistent, tip recurved, 5-many seeded).

Description.

Annual herbs, erect or sub-erect, branched from the base 10-15 cm high. Stem terete, sparsely villous, nodes red swollen, internodes 1.5-2 cm long. Leaves whorled, sessile, lanceolate-oblanceolate, green, 1.3-2.1cm long, base round, margin smooth or wavy, apex acute or acuminate, abaxial surface glabrous, adaxial surface pubescent; lamina 1-2 veined, prominent on abaxial side; stipules prominent, oblong, parted into 3 (2 equal barbellate parts), central part has a long acicular structure ca. 1 mm long, fused at the base (1-1.2 × ca. 0.4 mm), base golden yellow, smooth; margin entire, apex acicular, milky white. Inflorescence terminal, branched regular dense cyme, ca. 4.5 cm long; Bracts linear - lanceolate, 0.8 - 1.0 mm, white, equal or sub-equal to the length of the sepal; base smooth, margin entire, apex acicular. Bracteole capillaceous with acicular apex, holding the bracts in position. Flowers 4-6 per cyme, 3.5-3.8 mm long; pedicels 1.5-2.3 mm long, green villous. Sepals 5, fused at base, ovate (1-1.2 × ca. 0.8 mm), entire at the margin, acute to obtuse at apex, white, non-membranous base round, midrib faint. Petals 5, broadly wedge shaped (0.5-1 × 0.5-0.6 mm), margin entire, completely enclosing the ovary, 1/3 as short as sepals, whitish-lilac. Stamens 5, forming a ring with petals and encircling the ovary, ca. 0.9 mm long; anthers yellow, ovate, basifixed. Ovary 1-loculed, shortly stipitate, spheroidal, yellowish green, 1.2-1.3 × 1-2 mm, glabrous, placentation free central; style 0.01-0.03 mm, shorter than the ovary; stigma capitate. Capsule oblate-prolate (1.4-1.6 × ca. 0.6 mm), shortly stipitate, style not persistent, tip not recurved, 3-valved, breaks along the suture, brownish, scarious along margin. Seeds (2-3) ovate (0.1-0.15 × 0.1-0.2 mm), yellow with striations.

Micromorphology of the seed is ovate-sub-orbicular in its outline with depressions all over the seed surface. The margin is entire and the epidermal cell pattern is faintly angular. Striations are also faint (Fig. 7I, J ).

Phenology.

Flowering and fruiting during August-December.

Etymology.

Latin barba, stiff hairs, suffix ella, diminutive, and -ata, possession, alluding to barbellate nature of stipules, a diagnostic character.

Habitat and distribution.

The primary habitat of Polycarpaea barbellata is the hillock terrains in Palakkad district (Kerala granite outcrop in the northern side of Palakkad gap, the largest break in the Western Ghats having an arid climate with seasonal fires). Polycarpaea barbellata is also seen associated with Polycarpaea corymbosa , Fimbristylis sp. and Indigofera enneaphylla (Fig. 8 ).

Conservation status.

The present study could report two populations with 20-35 individuals each. We consider that further evidence is needed to determine the new taxon’s conservation status because Polycarpaea barbellata could be found in other regions in Southwest (and India as a whole). As a consequence, the new species is now categorized as DD (Data Deficient) by the IUCN ( IUCN 2021).

Additional specimens examined.

India. Kerala, Palakkad district, Kuzhalmannam, Kariyanchirachola , 2 November 2021, Suresh V. & Sojan Jose, 3077 (UCBD!); 10 November 2021 Alen Alex Philip & Suresh V., 3084 (UCBD!) .

Taxonomic notes.

In India, the genus Polycarpaea is represented by seven species ( Arya et al. 2021). The proposed three new species are closely allied to Polycarpaea corymbosa ( Linnaeus 1753: 205) Lamarck (1792: 129) and Polycarpaea aurea that has wide distribution along with P. palakkadensis . The new species also resembles Polycarpaea palakkadensis superficially but differs distinctly with respect to characters summarized in Table 1 .

Figures

Figure 5. A habit B flower bud C internode D flower E bract F stipule G sepal H petal I stamen J gynoecium K capsule L seed. Photos by V. S. A. Kumar.

Figure 6. Polycarpaea barbellata A habit B flower bud C flower D capsule E bract F stipule G petal H stamen I gynoecium J seed. Illustration by Ambika Viswanathanpillai.

Figure 7. SEM of seeds (P. corymbosa) A seed B seed surface C, D P. palakkadensis E, F P. ebracteata G, H P. psammophila I, J P. barbellata K, L P. aurea.

Figure 8. Distribution map of Polycarpaea ebracteata, P. psammophila and P. barbellata.