Chiloschista parishii Seidenfaden (1988: 176) var. minutiflora Aver., N.H.Tuan & V.C.Nguyen, 2022

Averyanov, Leonid V., Thai, Tran Huy, Truong, Ba Vuong, Nguyen, Van Canh, Nguyen, Tuan Hoang, Maisak, Tatiana V., Nguyen, Khang Sinh & Nguyen, Van Khuong, 2022, New orchids in the flora of Vietnam (Orchidaceae, Aeridinae), Phytotaxa 555 (2), pp. 113-135 : 115

Chiloschista parishii Seidenfaden (1988: 176) var. minutiflora Aver., N.H.Tuan & V.C.Nguyen var. nov.

( Figs. 1 C, D )

Type: — VIETNAM. S Vietnam, Dak Nong Province, Krong No District, Nam Nung Commune , shrubs along streams in evergreen forest at elevation 800–900 m a.s.l., flowers in April – May, 13 April 2018, Nguyen Van Canh , Nguyen Hoang Tuan, s.n. (holotype LE01042185 https://en.herbariumle.ru/?t=occ&id=332, photos LE01123088 https:// en.herbariumle.ru/?t=occ&id=134258) .

Etymology: —Variety name refers small size of its flowers.

Description:—Herb leafless, miniature, monopodial, with stem 3–4 mm long and many dense, flexuose, tufted, gray green roots 4–10 cm long. Inflorescence hairy, 2–2.5 cm long; scape 1.2–1.4 cm long, with 2–5 distant sterile triangular scarious bracts. Rachis 8–10 mm long with (2)3(4) flowers; floral bracts triangular, acute, scarious 1.5–2 mm long. Pedicel and ovary 1.8–2.2 mm long. Flowers yellowish, tepals speckled with brown, widely opening, 5.5–6 mm across; median sepal elliptic ovate, (3.4)3.5(3.6) mm long, (2.6)2.7(2.8) mm wide; lateral sepals distinctly smaller, obliquely broadly ovate, (2.1)2.2(2.3) mm long, (1.9)2(2.1) mm wide; petals triangular broadly ovate, (2.7)2.8(2.9) mm long and wide; lip 3-lobed, 1.5–1.6 mm long with erect obovate side-lobes (1.3)1.4(1.5) mm long. Fruit unknown.

Habitat, phenology and conservation status: —Epiphyte. Broad-leaved evergreen submontane forests and shrubs at elevations of 800–900 m a.s.l. Fl. April–May. Very rare. Suggested IUCN Red List status – DD.

Distribution: —Southern Vietnam (Dak Nong Province, Krong No District). Endemic.

Note: — Chiloschista parishii described from Myanmar ( Seidenfaden 1988) has a wide distribution in India, Nepal, Bhutan, Myanmar, China, Thailand, Laos and Vietnam. This species is very variable in floral morphology and coloration, and has relatively large flowers, commonly 8–12 mm across ( Pearce & Cribb 2002). Such plants were observed and collected in many areas in Vietnam, however, the small flowering variety recently discovered there has not been reported before. It has very similar floral structure to the typical variety C. parishii var. parishii , but differs in all parts of the flower, which are twice smaller, namely flower 5.5–6 mm across (vs. flowers 8–12 mm across), median sepal 3.4–3.6 mm long (vs. median sepal 5–6 mm long), lateral sepals 2.1–2.3 mm long (vs. lateral sepals 4–5 mm long), petals 2.7–2.9 mm long (vs. 5–6 mm long), and lip 1.5–1.6 mm long with side-lobes 1.3–1.5 mm tall (vs. lip and side-lobes 2.5–3 mm long). The new variety has so far only been found in the type locality and may be regarded as a narrow endemic. However, this small and unattractive plant may have a broader distribution but has possibly been overlooked. Under these circumstances, the IUCN conservation status may be tentatively assessed as Data Deficient DD.

Figures

FIGURE 1. Ascocentropsis malipoensis. A. Flowering plant (AL 1295), B. Flower, half side view (AL 1187). Chiloschista parishii var. minutiflora. C. Inflorescence. D. Portion of inflorescence with fully open flowers (Nguyen Van Canh, Nguyen Hoang Tuan, s.n.). Chiloschista sweelimii. E–G. Flowering plant, inflorescence and flower, half side view (Nguyen Van Canh s.n.). Cleisostoma equestre. H. Flowering plant, I. Flower, frontal view (AL 1123a). Photos by Nguyen Phi Tam (A), L. Averyanov (B), Nguyen Van Canh (C, D, H, I), and anonymous photo (E–G).