Amitostigma kaiyangense S. Z. He et Y. Wang, 2022

He, Shun-Zhi, Wang, Yong & Xu, Wen-Fen, 2022, Amitostigma kaiyangense (Orchidaceae), a new species from Guizhou, China, Phytotaxa 547 (1), pp. 115-118 : 115-118

Amitostigma kaiyangense S. Z. He et Y. Wang , sp. nov. ( Figure 1 , 2 )

Type :— China, Guizhou Province, Kaiyang County, on mossy cliff along a valley, elevation 900 m, 16 Jun. 2009, S. Z. He 090616 (holotype GZTM!; isotype PE!) .

Diagnosis:— Plant 10–17 cm tall. Tubers ovoid or oblong-ellipsoid, 1–2.3 cm long, 5–8 mm diam., fleshy. Stem slender, erect, glabrous, with two tubular sheaths at base and 1 subbasal leaf. Leaf spatulate-oblong or narrowly elliptic, 7–12 cm long, 2.8–3.8 cm wide, acuminate at apex, base contracted into amplexicaul sheath. Inflorescence 1 to 4-flowered; floral bracts lanceolate, 5–6 mm long, much shorter than ovary, 3-ridged, slightly twisted, glabrous, 1.8–2.3 cm long (including pedicel); flowers reddish spotted with purple-red; dorsal sepal ovate, 6–7 mm long, ca. 3.5 mm wide, erect, concavecymbiform, acuminate at apex; lateral sepals obliquely ovate, reflexed, 7–8 mm long, 4–5 mm wide, acuminate at apex; petals obliquely ovate, erect, 7–8 mm long, 5–6 mm wide, often 3-nerved, minutely ciliate-margined, acuminate at apex; lip spreading, flabellate, 1.4–2 cm long, 1.6–2.2 cm wide, trilobed near middle, with lobes irregularly denticulate-margined apically; side-lobes obovate-oblong, ca. 1 cm long, 1–1.2 cm wide, mid-lobe oblong, ca. 1 cm long, 0.8–1.0 cm wide, emarginate at apex; spur pendent, cylindrical, 1.7–2.1 cm long, slightly arcuate, obtuse at apex; column short, erect; anther narrowly ellipsoid, ca. 3.5 mm long, obtuse at apex; pollinia obovoid, ca. 1.5 mm long, 0.8 mm wide; caudicals ca. 1.5 mm long; viscidium subovate; rostellum small, erect, triangular; stigma 2-lobed, raised; staminodes 2, elliptic, small. Seed nearly oblong ( Fig.1 ).

Distribution: —Only found in type locality.

Ecology:— The species grows in mossy place on limestone cliff along a valley, at an elevation between 900 and 910 m.

Phenology:— Flowering period from June to July.

Taxonomic relationships:— This new species is similar to Amitostigma pinguiculum , from which it differs mainly by its distribution, flowering period and morphological characteristics, such as much broader leaf to 2.8–3.8 cm wide, lip trilobed near middle, lobes with irregularly denticulate-margined apically, side-lobes obovate-oblong and mid-lobe oblong. Detailed comparison of the two species is presented in Table 1 .

IUCN Red List category:— Amitostigma kaiyangense was found in an area of less than one square km., only 20 flowering individuals and no more than 100 plants (including seedlings) were seen scattered in mossy places on limestone cliffs along a valley. Therefore, A. kaiyangense is assessed here as Endangered (EN) according to IUCN Red List Criteria (less than 250 mature individuals), ( IUCN, 2001).

Figures

FIGURE 1. The habit of Amitostigma kaiyangense S. Z. He et Y. Wang. (A) Flowering plant in wild; (B) Flower, front view; (C) Flower, below view; (D) Flower, side view; (E) Seed, by SEM.

FIGURE 2. Amitostigma kaiyangense S. Z. He et Y. Wang (drawn by Xiang-Li Wu from the holotype). (A) Flowering plant; (B) Dorsal sepal; (C) Petals; (D) Lateral sepals; (E) Labellum; (F) Spur; (G) Pollinarium.