Zeuxine yonzoneana, Rajendra Yonzone, 2025

Yonzone, Rajendra, 2025, Zeuxine yonzoneana sp. nov. (Orchidaceae: Spiranthoideae: Cranichideae: Goodyerinae): a new species from India, Phytotaxa 712 (2), pp. 186-192 : 187-191

Zeuxine yonzoneana, Rajendra Yonzone sp. nov. ( Figs. 1–3 )

Plant terrestrial, rhizomatous herb, 14.4 cm tall, slender. Rhizome creeping, fleshy, properly imbedded in the soil, short, 2–3.5 cm long, 0.3–0.5 cm thick, whitish-green, rooting at nodes. Roots 1.5–2.4 cm long, 0.2–0.4 cm thick, fleshy with root hairs. Stem leafy, terete, soft, 9.9 cm tall, 0.3-0.35 cm thick, unbranched, erect, purple-green, pubescent, membranous sheaths with fresh leaf-bases, with fresh green leaves. Leaves 8, fresh at flowering, lamina 0.6–3.7 × 0.2–1.1 cm, glabrous, 3–5-veined, narrow-elliptic; petiole 0.5–0.9 cm long, sheathing at base, ovate to lanceolate, base obtuse, tip acute, 3-nerved, pubescent. Inflorescence terminal, raceme, laxly 11-flowered, yellowish-white, externally pubescent, peduncle 4.6 cm long, with 2–4 sheathing bracts, sheathing bracts 0.4–0.9 × 0.3–0.5 cm, lanceolate, apex acuminate, pubescent, 3-veined, rachis 2.7 cm long. Floral bracts 0.6–1.1 cm long, more or less equaling the ovary, narrowly lanceolate, apex abruptly acute, sparsely pubescent, 3-veined. Flowers small, minutely open, 0.4–0.6 cm long; pedicellate ovary 0.6–1.0 cm long, obliquely ribbed, green, minute white at the tip portion, pubescent. Sepals compactly arranged, sub-equal, greenish-white, pubescent with whitish tinge at apex, 1-veined; dorsal sepal 0.4–0.6 × 0.5–0.6 cm, basally greenish-grey, broadly ovate, apex acute, white; lateral sepals 0.4–0.6 × 0.2–0.25 cm, ovate-lanceolate, apex acute. Petals 0.4–0.5 × 0.1–0.15 cm, elliptic, oblique, apex acute, white, lower half greenish-grey, upper half white. Lip 0.45 × 0.55 cm long, unlobed, connate to the column, white with greenish-grey tinge, upper half white, lower half greenish-grey; hypochile, ca. 0.15 × 0.18 cm, saccate at base, curved; mesochile ca. 0.13 × 0.15 cm, linear, margin curved inwards; epichile unlobed, apex rounded, margin entire. Column 0.11–0.18 cm long, porrect with 2 appendages; rostellum ca. 0.13 cm long, apex obtuse, slightly curved. Anther ca. 0.3–0.35 cm long, bi-chambered; pollinia 2, ca. 0.1 cm long; light yellow, bifid caudicle ca. 0.05 cm long, viscidia oblong-elliptic, white, thick. Stigma 2-lobed, elliptic. Pedicellate ovary 0.7–1.1 × 0.15–0.28 cm, green, pubescent.

TYPE: INDIA , West Bengal, Darjeeling Himalaya, District Kalimpong, Kalimpong Block I, Samalbong Gram Panchayat, Samalbong Busty, 27º00 ’ 59.61 ” N, 88º29 ’ 43.37 ” E, 1011 m, 13 October 2017, Rajendra Yonzone 1484 A (holotype: CAL!; 1484 B, isotype: CAL!; 1484 C, isotype: VICBOT!).

Diagnosis: Zeuxine yonzoneana is completely unmatchable with other species of Zeuxine but partially allied to Z. clandestina , however, it is quite distinct from this species in having non–withered leaves during anthesis, flowers slightly open, ovate-lanceolate lateral sepals; broadly elliptic petals with acute apex; lip unlobed, as long as sepals and petals; mesochile margin incurved inwards, epichile unlobed with entire margins; bracts attached with pedicellate ovary; flowering month September–October vs withered leaves, ovate-oblong shaped lateral sepals, oblong-falcate petals with sub-acute to obtuse apex; lip distinctly bilobed, white, longer than sepals and petals, serrated epichile margins; bracts reflexed downwards; flowering month February–April of the later.

Flowering and fruiting: September–January.

Habitat Ecology and available flora: The new species was found growing among leaf litter of Schima wallichii (DC.) Korth. (1842: 143) , on slopes in undulate rocky sub-temperate region with associated plants of Bambusa nutans Wall. ex Munro, (1868: 92) , and other surrounding herbaceous plants like Imperata cylindrica (L.) Raeusch. (1797: 10), Dienia ophrydis (J. Koenig) Seidenf. (1997: 18) , Habenaria dentata (Sw.) Schltr. (1919: 125) , Agave americana L. (1753: 323), Ageratum conyzoides L. (1753: 839), Ageratina adenophora (Spreng.) R.M. King & H. Rob. (1970: 211) , Nephrolepis cordifolia (L.) C. Presl. (1836: 79), Lantana camara L. (1753: 627), Chromolaena odorata (L.) R.M. King & H. Rob. (1970: 204), Melastoma malabathricum L. (1753: 390), Neyraudia reynaudiana (Kunth) Keng ex Hitchc (1934: 131) , and Clerodendrum infortunatum L. (1753: 637).

Distribution: The new taxon is only known from Darjeeling Himalaya region of West Bengal, India . The species grows on ground in dry bamboo grooves surrounded by Imperata cylindrica at about 1000m elevation.

Additional specimens examined (paratype): INDIA , West Bengal, Darjeeling Himalaya, District Kalimpong, Samalbong Gram Panchayat, Samalbong Busty, 27º00 ’ 48.56 ” N, 88º30 ’ 36.47 ” E, 1030m, 19 October 2020, Rajendra Yonzone 1497 A, 1497B, 1497C & 1497D (paratype: CAL!; NBU!; TOSEHIM!).

Etymology: The specific epithet “ yonzoneana ,” refers to the ‘Tamang’ Tribe community of Sub Tribe ‘Yonzone’ of Samalbusty Busty, under Samalbong Gram Panchayat, Post Office Sinji BO - 734301, Kalimpong Development Block I, District Kalimpong, West Bengal, India . The new species was found in the area where the tribe lives.

Taxonomic notes: The new species partially resemble to Zeuxine clandestina but unique and unmatchable taxonomic characters of new species are plant rhizomatous herb, 7.5–17.5 cm tall. Stem leafy, 6–11.5 cm tall. Leaves 4-8, fresh at flowering, 0.6–4.6 × 0.2–1.2 cm. Inflorescence terminal, raceme, laxly 5-many flowered, peduncle 1.4–4.6 cm long, rachis 2.4–3.5 cm long. Floral bracts 0.6–1 cm long. Flowers 0.4–0.6 cm long; pedicelate ovary pubescent. Sepals compactly arranged. Lip 0.45 × 0.57 cm long, unlobed; hypochile, ca. 0.15 × 0.18 cm, saccate at base; mesochile linear; epichile unlobed. Natural population is sparse in the type locality.

The difference in morphological characteristics between Zeuxine clandestina and Zeuxine yonzoneana are presented in Table 1.

Figures

FIGURE 1. Natural habitat of Zeuxine yonzoneana Rajendra Yonzone sp. nov.

FIGURE 2. Zeuxine yonzoneana Rajendra Yonzone sp. nov. A. Habit (Entire plant at blooming stage), B. Basal portion of plant with stem and leaves, C. Tuber with base of stem, D. Inflorescence (rachis), E. Side view of flower with pedicellate ovary, F. Front view of flower with pedicellate ovary and floral bract, F1. Ventral view of flower with pedicellate ovary and floral bract, F2. Pedicellate ovary, G. Side view of lip with pedicellate ovary, H. Floral bud with pedicellate ovary, I. Floral perigone, a. Dorsal sepal, b. Lateral sepals, c. Petals, d. Lip, J. Side view of lip, K. Dorsal view of lip, L. Front view of lip, M. Anther, N. Pollinia, O. Floral bracts. [Measurement in cm. & mm.]

FIGURE 3. Zeuxine yonzoneana Rajendra Yonzone sp. nov. A. Habit (Entire plant with inflorescence), B. Basal portion of plant with stem and sheathing leaves, C. Tuber with base of stem, D. Leaf, E. Inflorescence, F. Front view of flower with pedicellate ovary, G. Side view of flower, H. Ventral view of flower with floral bract, I. Floral bud with pedicellate ovary, J. Side view of lip with pedicellate ovary, K. Floral perigone, a. Dorsal sepal, b. Lateral sepals, c. Petals, d. Lip, L. Side view of lip, M. Front view of lip, N. Anther, O. Pollinia, P. Floral bracts. [Line drawing with measurement in cm. and mm.]