Gastrochilus pseudodresslerii C.Y. Zhou & M.H. Li

Zhou, Cheng-Yuan, Zeng, Meng-Yao, Wu, Yu-Wei & Li, Ming-He, 2024, Gastorchilus pseudodresslerii (Orchidaceae; Vandeae), a new species from China: evidence from morphological and DNA analysis, Phytotaxa 634 (1), pp. 71-78 : 74-77

Gastrochilus pseudodresslerii C.Y. Zhou & M.H. Li , sp nov. ( Figs. 2 , 3 (A–I))

Type: — CHINA. Yunnan: Maguan , epiphytic on tree trunks in evergreen broad-leaved forest, elev. ca. 1,500 m ; 9 September 2022, voucher (Zhou20220909; ZhouCS001) (holotype, FJFC!; isotype, CSH!) .

Diagnosis: The new species is similar to G. dresslerii Vuong, Aver. & V.S.Dang , from which it differs by the longer (1.5–2.1 cm vs. 0.8–1.3 cm) and broadly lanceolate to oblong leaves, larger (4.8–5.3 × 3.1–3.4 mm vs. ca. 4.0 × 2.0 mm) and elliptic dorsal sepal, longer (5.0– 5.2 mm vs. ca. 4.0 mm) petals, taller hypochile (5.7–5.9 mm vs. ca. 4.3 mm) and narrowed toward apex (vs. almost square) of column.

Epiphytic herbs. Stem pendulous, slender, often branched, up to 13 cm long, with purplish spots, internodes ca. 4–5 mm. Leaves alternate, distichous, broadly lanceolate to oblong, abaxially glossy and sometimes with purple-red spots on the mid-vein, 1.5–2.2 × 0.4–0.7 cm; apex acute and unequally 2-lobed with 1 awn, approximately perpendicular to stem. Inflorescence sub-umbellate, 3–4 flowered; peduncle 0.7–0.8 cm, upper part enlarged; floral bracts ovatetriangular, ca. 2.0 mm; pedicle and ovary yellow-green sometimes with purple-red spots, 0.7–1.1cm long. Flowers not widely opening, sepals and petals yellow-green with purple dots abaxially. Dorsal sepal elliptic, concave, apex rounded, 4.8–5.3 × 3.1–3.4 mm; lateral sepals hemisphere to obliquely elliptic, oblique, concave, 4.9–5.3 × 2.6–2.8 mm. Petals elliptic, apex rounded, 5.0–5.2 × 3.1–3.2 mm; lip white to greenish, divided into epichile and a saccate hypochile; epichile reniform to half-circular, narrowed toward apex, 2.9–3.1 × 6.7–6.9 mm, yellow cushion with densely white hairy and purple dots, 2.7–2.9 × 2.3–2.4 mm in diameter, margin with few hairy; hypochile saccate to subcupular, 5.7–5.9 mm tall, 3.6–3.8 mm wide, mouth with lateral pinkish stripes, inside with purple-red spots, outside glossy and with 1 ridge. Column short with purple spots, ca 2.0 mm; rostellum bifid, rostellar arms tapering; anther cap trapezoidal, the front part drawn out into a long beak, with two chambers, 1.1 × 1.3 mm; pollinia 2, subglobose, yellow, ca. 0.3 mm in diameter; stipe elongate, ca. 1.0 mm; viscidium elliptic, ca. 1.0mm long. Capsules fusiform to ellipsoid, with 3 ridges, 1.4–1.6 × 0.5–0.6 cm.

Phenology: —Flowering March to April.

Etymology: —The specific epithet is derived from the Greek ‘pseudo-’ (false) and after ‘ Gastrochilus dresslerii’ referring to its close similarity with G. dresslerii .

Distribution and habitat: — Gastrochilus pseudodresslerii is epiphytic on tree trunks of ca. 1,500 m at the edge of evergreen broad-leaved forests, known so far only from Maguan County, Yunnan Province, China.

Figures

FIGURE 2. Habitat and morphology of Gastrochilus pseudodresslerii. A. Habitat. B. Flowering plant. C. Inflorescence. D. Flower (front view). E. Leaves (adaxial and abaxial surface). F. Fruit. G. Sepals, petals, anther cap and pollinarium. H. Lip (front, lateral, top and back view).

FIGURE 3. Line drawings of Gastrochilus pseudodresslerii (A–I) and the related taxa (J–L). A. Flowering plant. B. Anther cap. C. Pollinarium. D. Dorsal sepal, petals and lateral sepals. E. Lip and column (lateral view). F. Lip and column (front view and top view). G. Flower. H. Leaves (adaxial and abaxial surface). I. Inflorescence on the plant. J. Flower of G. dresslerii (modified from Nguyen et al. (2021)). K. Flower of G. raraensis (modified from Hsu et al. (2018)). L. Flower of G. formosanus (modified from Kumar et al. (2014)).