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

Figs 1 , 2

Type.

India. Kerala, Palakkad district, Kollengode forest range, Nenmeni , Vengappara 10°34'33.6"N, 76°42'47.1"E, 160 m a.s.l., 20 September 2021, Suresh V., V.S.A. Kumar & Arya S., 2077 (holotype UCBD! isotype UCBD!) .

Diagnosis.

Polycarpaea ebracteata is morphologically similar to Polycarpaea corymbosa in terms of having prominent villous stem nodes and shape of petals but differs with respect to stipules (short, ovate less than 1mm, vs. lanceolate, long, 5 mm) bracts (absent vs. present), bracteoles (absent vs. present), sepals (ovate, acute at apex, not membranous vs. lanceolate, acuminate apex, hyaline, membranous), petals (dark brown, ovate-elliptical vs. whitish-pink, broadly ovate), stamens (filament reduced, 0.1 mm vs. filaments equal to the length of anther 1 mm), capsule (style not persistent, tips curved vs. style persistent, tips not curved) and seeds (3-4 or rarely 2, yellow, ovate vs. 5-13, brown, reniform).

Description.

Annual herbs, erect or sub-erect, branched at base, 2.5-8 cm high. Stem terete, densely villous, nodes green, swollen, internodes ca. 5 mm long. Leaves whorled or verticillate, sessile, linear, green, 0.7-0.9 cm long, base cordate, margins smooth, apex acute or acuminate, surface glabrous, blade 1-veined, prominent on abaxial side; stipules scarious, ovate-obovate, (0.2-0.8 × ca. 0.6 mm), margins entire, acute, not nerved, yellowish or greenish at the base, white above. Inflorescence terminal, branched cyme, ca. 1.0 cm long; Flowers 2.2-2.6 mm long; Bracts absent. bracteoles absent; pedicels 1.0-1.3 mm long, green, villous. Sepals 5, free, ovate (1.3-1.4 × ca. 0.7 mm), entire at the margin, acute or obtuse at apex, white, non-membranous base round, midrib not prominent. Petals 5, ovate (0.1-0.3 × 0.1-0.3 mm), margins entire, oblong to round at apex, partially enclosing the ovary, 1/4 as short as sepals, dark red-brown. Stamens 5, forming a ring with petals and encircling the ovary, ca. 0.2 mm long; anthers yellow, oblong, basifixed. Ovary 1-loculed, shortly stipitate, spheroidal, 0.3-0.5 × 0.1-0.2 mm, glabrous, placentation free central; style 0.08-0.1 mm, shorter than the ovary, slender; stigma capitate. Capsule ovoid (1.4-1.6 × ca. 0.6 mm), shortly stipitate, 3-valved, breaks along the suture, brownish, scarious along margin. Seeds 3-4 (rarely 2), ovate (0.2-0.3 × 0.1-0.2 mm), yellow with no striations.

Micromorphology of the seed shows that it is round-oblong with a winged margin. The surface has sub parallel striations which are prominent. The striations do not cross each other and the encircling surface of the striations are punctate. Along the margins, the surface has parallel striations (Fig. 7E, F ).

Etymology.

Latin prefix e-, without, bractea, bract, and suffix -ata, possession, alluding to absence of bracts, a diagnostic character.

Phenology.

Flowering and fruiting during August - December

Distribution and habitat.

The primary habitat of Polycarpaea ebracteata is the hillock terrains in Palakkad district (Granite outcrop in the southern side of Palakkad gap, the largest break in the Western Ghats having an arid climate with seasonal fires, in the state of Kerala). One of the common species that emerges after the initial rain are members of the Genus Polycarpaea , especially Polycarpaea aurea ( Wight 1850: 44) Dunn (1915: 65). Polycarpaea ebracteata is seen associated with Allmania nodiflora (L.) R. Br. ex Wight, Indigofera aspalathoides DC. and Fimbristylis cymosa R. Br. (Fig. 8 ).

Conservation status.

The present study could report only three populations each with 15-20 individuals. Since Polycarpaea ebracteata could occur in further sites in SW-India (and India as a whole), we think that further data is 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).

Additional specimens examined.

Polycarpaea ebracteata India. Kerala, Palakkad district, Kollengode , Cheerani. 12 September 2021, Suresh V. & Alen Alex Philip, 2061 (UCBD!); 20 September 2021, Sojan Jose & Suresh V, 2078 (UCBD!) .

Figures

Figure 1. Polycarpaea ebracteata A habit B flower C flower bud D stipule E, F sepal G petal H gynoecium I capsule J seed. Photos by Arya Sindhu.

Figure 2. Polycarpaea ebracteata A habit B flower C stipule D, E sepal F petal G gynoecium H capsule I 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.