Euphorbia kadapensis Sarojinidevi & Venkataraju, 2014

Sarojinidevi, Naidu & Reddivenkataraju, Rudraraju, 2014, Euphorbia kadapensis (Euphorbiaceae), a new species from southern India, Phytotaxa 181 (3), pp. 179-183 : 179-182

Euphorbia kadapensis Sarojinidevi & Venkataraju , sp. nov. ( Figs. 1 , 2 )

Type:— INDIA. Andhra Pradesh: Kadapa district, Palakonda hills, Mabbuchinthalapalle , 14°20’54.16’’N, 78°15’05.41’’E, 372–380 m, 5 October 2011, N . Sarojinidevi & R. R . Venkataraju 31413 (holotype SKU!, isotypes BSID!, MH!) .

Diagnosis:— The new species is very distinct from the known species of the genus from the territory by virtue of its glabrous shoots, long free styles, obscurely venulose cocci and tuberculate seeds. It is allied to the long-styled species from the peninsula on one hand, namely the sympatric E. longistyla and E. senguptae with its tapering shoots, elliptic leaves and long styles, and on the other to the allopatric E. concanensis from Konkan coast in vegetative traits but differs in the morphology of limbs of glands, ebracteolate staminate flowers, simple and discrete stigmas and etuberculate seeds. E. senguptae can be easily segregated by the limbs of glands which are minutely wavy and E. longistyla with its incised limbs of glands

Description:— Erect, decumbent to ascending herb (hemicryptophyte) up to 30 cm tall. Latex milky. Stem sympodial, dichotomously branched. Branches terete, glabrous, pink, filiform towards apices, sparsely hairy, hairs hyaline; internodes 1–2.5 cm long, thickened at nodes; stipules scaly, connate, 0.1 cm long, shortly laciniate. Leaves simple, opposite, equal, inequilateral, subsessile; petiole 0.1 cm long, sparsely hairy; lamina ovate to elliptic, 1.0–2.5 × 0.4–0.6 cm, glabrous, oblique at base, margin serrulate and more so distally, apiculate, midrib prominent, nerves slightly distinct on adaxial surface, in 6–8 pairs. Cyathia terminal, at times axillary, 1–2, 0.6–0.9 cm long; peduncles 0.2 cm long; involucre turbinate ( Fig. 2C ), 4 × 2 mm, glabrous, alternately pink and green; involucral lobes 5, laciniate; appendages of glands 4, 2–3-fid up to half of its length ( Fig. 2F ) and occasionally to the base, 2 × 1 mm, pink; glands 4, oblong, yellowish green to brown, stipitate, stalks hairy; staminate florets 15–18, exserted, 1.5 mm long, pink, bracteate; bract simple, 2 mm long; anther lobes subglobose, dehiscing transversely, yellow ( Fig. 2E ); pistillate flowers laterally pendulous, 0.5 × 0.3 cm, glabrous, pedicel 0.5 cm long, knobbed distally ( Fig. 2C ); ovary tricarpellate; styles 3, free from base, 0.2 cm long; stigmas 3, simple, pink. Fruiting pedicels recurved ( Fig. 2D ), capsules schizocarpic, trigonous, distinctly keeled, prominently ridged along sutures, glabrous ( Fig. 2G, H ); cocci obscurely venulose. Fruits 3.5 mm long. Seeds 3 per capsule, ecarunculate, 1.5 × 1.0 mm oblong-ovoid, tetragonal, transversely and obscurely furrowed, truncate at base, not tuberculated, brown ( Fig. 2I ).

Etymology:— The specific epithet refers to the area (Kadapa district) of its occurrence, i.e., the Rayalaseema region in southern India ruled by Sri Krishnadevaraya who reigned the Vijayanagar Empire in 1509–1529 Common era.

Phenology:— Flowering and fruiting from September to December.

Distribution and habitat: —Endemic to the Palakonda hills, Kadapa district, Eastern Ghats, Andhra Pradesh, India known only the type collection. The individuals of Euphorbia kadapensis were found on black gravelly soil, interspersed with calcium rocks of a scrub forest in Mabbuchinthalapalli of Kadapa district, at an elevation range of 372– 380 m. The prominent associates in the community are herbs like Polycarpaea corymbosa ( Linnaeus 1753: 205) Lamarck (1797: 129) , the grass Cymbopogon coloratus ( Hooker 1896: 206) Stapf (1906: 321) , shrubs such as Searsia mysorensis ( Don 1832: 74) Moffett (2007: 170) , Carissa spinarum Linnaeus (1771: 559) , and the woody exotic invasive Prosopis juliflora ( Swartz 1788: 85) Candolle (1825: 447) .

Conservation status:— According to the criteria of the IUCN Red list ( IUCN 2001), it is Vulnerable VU, D 1+2. The current species range is estimated to be less than 2 km 2, with less than a thousand individuals. The habitat is severely fragmented and degrading due to grazing, land claims by local people for cultivation, etc.

Comparison: —The new species is allied to and resembles Euphorbia concanensis (Konkan spurge) from the Konkan coast, Shindudurg district of Maharashtra ( Janarthanam & Yadav 1995) in the habit and bearing prominent keels and sutural ridges to the ovary and capsules. However, E. kadapensis is different in a number of characters, as keyed out below:

1a. Limbs of cyathial glands subequal, obovate, entire-wavy, 2.5 × 2.6 mm; staminate florets ebracteolate; stigmas bifid; seeds grey, 1.1 × 0.8 mm, tuberculate................................................................................................................................... E. concanensis

1b. Limb of cyathial glands equal, oblong, laciniate and deeply 2–3-fid, 2.0 × 1.0 mm; staminate florets bracteolate; stigmas simple; seeds brown, 1.5 × 1.0 mm; etuberculate ...................................................................................................................... E. kadapensis

Discussion: —The new species is characterized by herbaceous habit, copious milky latex, opposite stipulate leaves with Kranz anatomy and basic anisocytic stomata, floral leaves not concealing the involucres, gland appendages conspicuous and 1–2-times larger than the glands, cocci of the fruits prominently keeled and ridged in between the carpels, styles long and free, and seeds ecarunculate. Several of these features are typical of the traditional Euphorbia subgen. Chamaesyce which was often segregated earlier as a distinct natural genus Chamaesyce Gray (1821) ( Webster 1967, Raju & Rao 1987). The newly circumscribed Euphorbia subgen. Chamaesyce ( Bruyns et al. 2006) contains around 600 species and includes the largest New World radiation within the Old World-centered genus Euphorbia . Based on nuclear ribosomal ITS and chloroplast ndhF sequences, the subgenus Chamaesyce was divided into 15 sections ( Yang et al. 2012) of which sect. Anisophyllum has two subsections, Acutae Boissier (1862: 18) and Hypericifoliae Boissier (1862: 20). The new species described belongs to the latter subsection which is characterized by triangular or ciliate, subulate non-glandular stipules. The sect. Longistylae Binojkumar & Balakrishnan (2010: 178), erected to accommodate the endemic therophytic Indian taxa with E. longistyla Boissier (1860: 8) as the type, was reduced to subsect. Hypericifoliae by Yang et al. (2012).

Euphorbia kadapensis resembles Euphorbia concanensis Janarthanam & Yadav (1995: 148) and certain other members of the Euphorbia subgen. Chamaesyce sect. Anisophyllum Roeper (1828: 412) subsect. Hypericifoliae Biosser (1862: 20) and Yang et al. (2012: 781) or sect. Longistylae Binojkumar & Balakrishnan (2010: 178) in the general morphology and differs sufficiently to be described as a distinct species.

In addition to E. concanensis , E. kadapensis also resembles the local endemics E. longistyla and E. senguptae Balakrishnan & Subramanyam (1960: 175) in the tapering shoots, elliptic to oblong-elliptic leaves and long styles. However, the appendages of the cyathial glands are 2–3–fid in E. kadapensis , compared to entire and minutely wavy in both E. senguptae and E. concanensis . Euphorbia kadapensis shares free, long and simple styles and incised appendages of glands with E. longistyla . However, in E. longistyla glands are green and the appendages of the cyathial glands are multifid and laciniate. Moreover, E. kadapensis is distinctive from all three species in having glabrous branches and obscurely venulose cocci.

Figures

FIGURE 1. Euphorbia kadapensis. A. Habit. B. Cyathium. C. Ovary, top view. D. Capsule, bottom view. E. Staminate flower, with bracteole. F. Involucre split open, revealing the four glands with their petaloid limbs (note the hispid involucral lobes and stipitate of glands). G. Capsule with persistent styles and conspicuous ridges in between cocci. H. Seed. After Sarojinidevi & Venkataraju 31413; drawn by N. Sarojinidevi.

FIGURE 2. Euphorbia kadapensis. A. Habit. B. Typical branching. C. Cyathium, singled out. D. Cyathium, in position. E. Two staminate florets: one at anthesis with bracteole and the other young. F. Involucre split open. G. Ovary, top view. H. Capsule, bottom view (note the conspicuous ridges abutting the sutures). I. Seeds. Photo credits: N. Sarojinidevi.