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

Figs 3 , 4

Type.

India. Kerala, Palakkad district, Nenmara, Ayinampadam , 10°35'29.4"N, 76°34'48.2"E, 140 m a.s.l., 21 September 2021, Suresh V. & Arya S., 2081 (holotype UCBD! isotype UCBD!) .

Diagnosis.

Polycarpaea psammophila is morphologically similar to Polycarpaea corymbosa with respect to the whorled arrangement of leaves and pilose nature of stem but differs with respect to stipules (linear to lanceolate with acuminate apex vs. lanceolate-ovate, with acute apex), bract (lanceolate-oblanceolate white, exceeding the length of sepal vs. lanceolate-ovate, shorter than the sepal), bracteoles (linear with acicular apex vs. lanceolate with acute apex), petals (ovate - oblate, keeled, dark brown, apex pointed upwards vs. broadly ovate, not keeled, whitish-pink, round at apex), gynoecium (oblate spheroidal, reddish yellow vs. ovate short, green), capsule (four valved vs. three valved) and seeds (20-25 yellowish brown, ovate vs. 5-13, brown, reniform).

Description.

Annual herbs, erect or sub-erect, 18-25 cm high. Stems terete, densely villous, nodes green, swollen, internodes ca. 1.5-2 cm long. Leaves whorled, sessile, linear-lanceolate, green, 2.3-3.1cm long, base round, margin smooth, daggered in young leaf, apex acute or obtuse abaxial surface glabrous, adaxial surface pubescent along the mid vein; blade 1-2 veined, prominent on abaxial side; stipules prominent, linear to lanceolate, fused at the base (5-8 × ca. 2 mm), base golden yellow with unicellular setae; setae hyaline; margins entire, often bifurcated into two, branches acicular at apex, not nerved, milky white. Inflorescence terminal, irregular, branched lax cyme, ca. 10 cm long; Bracts lanceolate-oblanceolate, exceeding the length of the sepal (2.0 - 2.3 × ca. 0.3 mm); base smooth, margin entire, apex acuminate. Bracteole 1.3mm linear with acicular apex, holding the bracts in position. Flowers 8-10 per cyme, 4-5.5 mm long; pedicels 1.0-1.3 mm long, green villous. Sepals 5, free, obovate-oblanceolate (2.3-2.6 × ca. 0.7 mm), entire at the margin, acute or obtuse at apex, white, non-membranous base round, midrib faint. Petals 5, ovate-oblate (1-1.3 × 1.1-1.3 mm), margin entire, keeled, pointed upward at apex, partially or completely enclosing the ovary, 1/2 as short as sepals, dark red-brown. Stamens 5, forming a ring with petals and encircling the ovary, ca. 0.3 mm long; anthers yellow, oblong, basifixed. Ovary 1-loculed, shortly stipitate, spheroidal, reddish-yellow 1.2-1.3 × 1-2 mm, glabrous, placentation free central; style 0.2-0.3 mm, shorter than the ovary, often very reduced and slender; stigma capitate. Capsule oblate-prolate (1.4-1.6 × ca. 0.6 mm), style persistent, shortly stipitate, 4-valved, breaks along the suture, brownish, scarious along margin. Seeds (20-25) ovate (0.2-0.3 × 0.1-0.2 mm), yellowish brown with striations.

Micromorphology of the seed exhibits a sub-orbicular shape with striations that are not parallel and cross each other towards the margin. The epidermal cell pattern is angular to spheroidal. Seed margin is entire and along the margin the cells are rectangular shaped (Fig. 7G, H ).

Phenology.

Flowering and fruiting during August- December.

Etymology.

Greek psammos, sand, and philios, loving, alluding to exclusive habitat of sandy marginal zones of granite hills.

Habitat and distribution:

The primary habitat of Polycarpaea psammophila is the hillock terrains in Palakkad district along the sandy margins. It is seen associated with Tephrosia purpurea (L.) Pers., Parasopubia delphiniifolia (L.) H.-P. Hofm. & Eb. Fisch. and Glinus oppositifolius (L.) A. DC. (Fig. 8 ).

Conservation status.

The current study is based on two different populations ranging from 50-80 individuals. We believe that further data is needed to determine the conservation status of Polycarpaea psammophila because it could be found in other locations in SW-India (or India as a whole). As a result, according to IUCN criteria, the new species is classified as DD (Data Deficient) ( IUCN 2021).

Additional specimens examined.

India. Kerala, Palakkad district, Nenmara, Vallangi , 12 September 2021, Suresh V. & Alen Alex Philip, 2065 (UCBD!); 21 September 2021, Sojan Jose & Kumar V.S.A., 2083 (UCBD!) .

Figures

Figure 3. Polycarpaea psammophila A habit B inflorescence C internode D flower cluster E flower F bract G bracteole H petal I stamen J sepal K stipule L gynoecium M capsule N seed. Photos by Suresh V.

Figure 4. Polycarpaea psammophila A habit B flower C stipule D bract E bracteole F sepal G petal H stamen I capsule 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.