Eriocaulon idukkianum Manudev, Robi & Nampy, 2017

Manudev, K. M., Robi, A. J. & Nampy, S., 2017, Eriocaulon idukkianum, a new tuberous species of Eriocaulaceae from southern Western Ghats, India, Phytotaxa 324 (3), pp. 288-292 : 289

Eriocaulon idukkianum Manudev, Robi & Nampy , sp. nov. ( Figure 1 )

The new species is allied to E. tuberiferum but differs in having a long root stock with single terminal tuber, free male sepals and seeds without appendages as opposed to 2–15 root tubers, spathaceously fused male sepals and seeds with appendages in the form of continuous ribbon like bands from the transverse and longitudinal radial walls conforming to its length.

Type:— INDIA. Kerala, Idukki district, Munnar , Silent Valley , ± 2200 m elevation, 16 December 2012, K. M. Manudev & A. J. Robi 4483 (Holotype CALI!; isotypes DEV!, MH!)

Acaulescent herbs. Root stocks up to 5 cm long with a terminal subterranean tuber; tuber globose, c. 1 × 1 cm, glabrous, cream. Leaves many, rosulate, linear-oblong, 5–7 × 0.2–0.4 cm, entire, glabrous. Peduncles 1–9, slender, 15–26 cm long, glabrous; sheaths to 7 cm long, limbs 3 or 4-lobed, glabrous. Involucral bracts ovate, elliptic or obovate, 2.9—3.5 × 1.5–2 mm, obtuse, coriaceous, glabrous, straw coloured or darker. Heads cylindrical, white. Receptacles cylindrical, pilose. Floral bracts oblanceolate, 2.5–3.0 × 0.5–0.7 mm, acuminate, pilose, hoary dorsally towards apex, black. Male flowers: Pedicels c. 1 mm long, glabrous. Sepals 3, free, subequal, oblanceolate, 1.3–1.5 × 0.4–0.5 mm, conduplicate, obtuse, hoary dorsally towards apex, black. Stipe of corolla c. 0.8 mm long, glabrous. Petals 3, unequal, oblong; lateral ones 0.5–0.6 mm long; odd one up to 1 mm long, hoary with a black gland. Anthers 6, oblong to globose, white. Female flowers: Pedicels c. 0.5 mm long. Sepals 3, free, subequal, oblong-oblanceolate, 2.3–2.6 × 0.5–0.7 mm, navicular, minutely keeled, pilose, acute, hoary towards apex, black. Petals 3, free, subequal, spathulate, not clawed, 2.2–2.5 mm long, hyaline, pilose, hoary with a black gland. Ovary sessile, c. 0.7 × 0.8 mm. Seeds ovoid, c. 0.6 × 0.5 mm, yellowish brown; cells of seed coat transversely elongated, arranged in longitudinal rows; appendages absent.

Etymology:—The specific epithet ‘ idukkianum’ refers to the type locality.

Notes:—Presence of a subterranean tuber in this genus was so far known only in E. tuberiferum which is characteristic with 2–15 globose or ovoid root tubers in each plant. However, E. idukkianum is unique in having a root stock which bears a single terminal tuber. It is observed that the length of rootstock increases as the plant matures. A detailed morphological comparison of the allied species is given in Table 1.

Distribution & ecology:—Growing in grasslands, marshes near streams and among the mosses growing luxuriantly in rock crevices.

Phenology:—Flowering and fruiting October to December.

Additional specimens examined:— INDIA. Kerala: Palakkad district, Koodam, Silent Valley National Park, ± 2300 m elevation, 31 October 2013, Manudev 135136 (CALI).

Conservation status:— Eriocaulon idukkianum is endemic to Kerala, known from two populations in Idukki and Palakkad districts of Kerala which are approximately 200 kms apart. According to IUCN criteria, the species falls under the category Data Deficient (DD) ( IUCN 2001, 2010).

Figures

FIGURE 1. Eriocaulon idukkianum Manudev, Robi & Nampy: A. Habit; B. Rootstock with a terminal tuber; C. Heads; D. Outer involucral bract; E. Inner involucral bracts; F. Floral bract; G. Male flower; H. Female flower-side view; I. Female flower-top view; J. Seeds (All from K.M.Manudev & A.J.Robi 4383).