Eriocaulon meenachilense Anoop & Robi, 2021

Anoop, P. B. & Robi, A. J., 2021, Eriocaulon Meenachilense, A New Tuberous Species Of Eriocaulaceae From The Southern Western Ghats, India, Edinburgh Journal of Botany 78 (336), pp. 1-8 : 2-5

Eriocaulon meenachilense Anoop & Robi , sp. nov.

Eriocaulon meenachilense resembles E. tuberiferum A.R.Kulk. & Desai in its root tubers, short, linear leaves and free female sepals. However, the new taxon differs in its solitary, 6-angled peduncle, short sheath, white inflorescences, inflexed involucral bracts, free male sepals, eglandular petals, yellow anthers and unappendaged yellow seeds. It also similar to Eriocaulon idukkianum Manudev, Robi & Nampy , another tuberous species from the Western Ghats that has linear leaves, white inflorescences, male flowers with free sepals and unappendaged seeds, but differs from that species in the absence of a root stock, its hairy, not glabrous root tubers, its solitary, 6-angled peduncle, and its glabrous receptacle, eglandular petals and yellow anthers and seeds

. – Type: India, Kerala, Kottayam District, Meenachil , Illikkal Hills , c. 1000 m a.s.l., 7 x 2019, Anoop. P. B. & A. J. Robi 15934 (holotype MH!, isotype BAM!, MBGH!). Figures 1 , 2 .

Acaulescent herb. Rootstock absent; root tubers 2 or 3, subglobose, 5–6 × 4–5 mm, villous, cream-coloured. Leaves rosulate, linear-subulate, stiff, 2.5–3.5 × 0.1–0.2 cm, glabrous, 3- or 4-nerved, nervules inconspicuous. Peduncle solitary, 12–20 cm high, 0.4–0.5 mm across, 6-angled, twisted, glabrous; sheaths 2–3 cm long, glabrous, striate; limb 1.5–2.5 mm long, incised. Inflorescence hemispherical, 5–6 × 4–5 mm, white. Receptacle convex, glabrous. Involucral bracts inflexed, obovate, acute at apex, 1.2–1.5 × 0.8–1 mm, black-hyaline, entire, chartaceous, glabrous. Floral bracts oblanceolate, acuminate, 1.2–1.5 × 0.6–0.8 mm, black, hoary towards apex. Staminate flowers: pedicels 0.1–0.2 mm long, glabrous; sepals 3, free, broadly oblanceolate, 1–1.2 × 0.3–0.4 mm, hyaline, hoary towards apex; corolla hyaline; stipe of corolla 0.8–1 mm long; lobes 3, subequal, obtuse and hoary towards apex, 0.3–0.4 × 0.1–0.2 mm, eglandular. Stamens 6, exserted; filaments 0.2–0.3 mm, white; anthers subglobose, 0.25 × 0.2 mm, yellow. Pistillate flowers: pedicels 0.1–0.2 mm; sepals 3, free, oblanceolate, 1.3–1.5 × 0.4–0.5 mm, keeled along back, obtuse and hoary towards apex, hyaline. Petals 3, almost equalling sepals, oblanceolate, obtuse and hoary towards apex, 1–1.2 × 0.2–0.3 mm, eglandular. Ovary subsessile, ovoid, trigonous, 0.3–0.4 × 0.2–0.3 mm; style 0.2–0.3 mm; stigmas 3, 0.8–1 mm long. Seeds obovoid-ellipsoid, 0.3–0.4 × 0.2–0.3 mm, golden yellow; cells of seed coat transversely elongated, aligned in vertical rows; appendages absent.

Distribution. Eriocaulon meenachilense is known only from the type locality, the Illikkal Hills in the southern Western Ghats, India ( Figure 3 ).

Phenology. Flowering and fruiting from August to November.

Etymology. The specific epithet refers to the type locality, Meenachil Taluk in Kottayam District, Kerala, India.

Habitat and ecology. Wet rocky grasslands in association with Eriocaulon thwaitesii Körn. , Exacum sessile L., Impatiens stolonifera Robi & Manudev , Phyllocephalum scabridum (DC.) K.Kirkman , Smithia bigemina Dalzell , etc.

Conservation status. Eriocaulon meenachilense is endemic to the southern Western Ghats, India. The authors located 42 plants in four groups within an area of 200 m 2. More extensive field surveys are required to better understand the true extent of occurrence and area of occupancy of this species. According to IUCN criteria, the species falls under the category Data Deficient ( IUCN, 2012; IUCN Standards and Petitions Subcommittee, 2019).

Eriocaulon tuberiferum has so far been reported from the northern Western Ghats in Maharashtra State and southern Western Ghats in Kerala State ( Sunil et al., 2018). The species is usually seen in the margins of puddles and open wet rocky slopes at 900–2100 m elevation. Eriocaulon idukkianum is confined to the southern Western Ghats in Kerala State and generally found at 2000–2300 m elevation in marshes near streams and rock crevices, in association with mosses. The major characters differentiating Eriocaulon meenachilense from the two other Indian tuberous species are listed in the Table.

Figures

Figure 1. Eriocaulon meenachilense Anoop & Robi, sp. nov. A, Habit; B, root tubers; C, involucral bract; D, floral bract; E, male flower; F, female flower; G, seed. Drawn from the holotype, Anoop. P. B. & A. J. Robi 15934 (MH), by P. B. Anoop.

Figure 2. Eriocaulon meenachilense Anoop & Robi, sp. nov. A, Habit; B, root tubers; C, sheath; D, twisted peduncle; E, head (side view); F, head (lower view); G, involucral bract; H, floral bract; I, male flower; J, male sepal; K, anther; L, female flower; M, female sepal; N, female petal; O, light and scanning electron microscopic images of seed. All from Anoop. P. B. & A. J. Robi 15934.

Figure 3. Map showing distribution of Eriocaulon idukkianum, E. meenachilense and E. tuberiferum in India.