Chamaegastrodia guidongensis L. Wu, H. Z. Tian & C. Z. Huang 2022, sp. nov

Chamaegastrodia guidongensis L.Wu, H.Z.Tian & C.Z.Huang, sp. nov. (Fig. 2, 3) Type: — CHINA. Hunan: Guidong County, Dongluo Village, 765 m, 20 July 2021, flowering period, A . Liu, Y. K. Gong & M. Z. Huang LK1671 (holotype: CSFI!, isotype: HSNU!); CHINA. Hunan: Guidong County, Dongluo Vilage, 12 October 2020, fruiting period, H. L . Liu et al. 30145 (paratype: HNNU!) Diagnosis: —The new species is distinct from other Y-shaped and T-shaped lip species of Chamaegastrodia by its unique canoe-shaped lip. It is most close to C. vaginata, but distinguishes by the lip and 2 triangular fleshy wings attached to the apex of column. Description: —Plant 10–25 cm, leafless. Rhizome, stout, 3–8 mm in diam., fleshy, translucent, glossy, light yellow to pale hazel red, with sparse short branches; mature branches ca. 8 mm, short, coralloid, brown to white fading from base to apex; sparse short fiber no more than 3 mm, slender. Stem 7–20 cm, ca. 3 mm diam., erect, pale hazel, covered with overlapping sheathing scales; scales 7–15 mm, decurrent at base and acuminate to abruptly tapered at the apex, pale-hazel in color, translucent, membranous, with short fleshy puberulent. Inflorescence with 3–9 flowers, puberulous rachis ca. 3.3 cm, elongating during fruiting; floral bracts, ca. 7 mm, as 2/3 the length of the ovary, ovate to lanceolate, orange-yellow to pale brown, depth and reverse warping at apex, with uneven surface; pedicel and ovary fusiform, ca. 8 mm, finely puberulous. Flowers non-resupinate; sepals fawn-colored, orange-yellow at apex, translucent, membranous, densely puberulous externally; dorsal sepal ca. 1.7 × 4.5 mm, ovate, acute, with many parallel distinct veins; lateral sepals ca. 6.4 × 3.1 mm, falcate, acute, with one distinct midvein and many parallel veins; petals ca. 4.8 × 2.3 mm, falcate, acute, pale yellow-orange at base, translucent, membranous, parallel veins only at apex; lip ca. 9.3 mm, canoe-shaped, margin wavy, folded inward, mid-part concaved with ridged midvein, wrinkled outside but smooth inside; hypochile dilated 3-times than epichile, concave-saccate wrapping the column up, yellow-orange, containing 2 sessile, sarcoma-shaped orange calli at base, one on each side of the sac; epichile, folded tightly, fawn; column ca. 5.0 × 2.2 mm, short, with 2 triangular, fleshy wings attached to apex vertically; anther ca. 0.8 × 0.1 mm, long-ovoid, attached to column via a short linear filament; rostellum forked, ca. 2.3 mm, erect, longer than the anther cap peak. Etymology: —The species epithet refers to the type locality, Guidong County, Hunan province. Chinese vernacular name:—桂东eạ兰 [guì dōng dié qiào lán]. Distribution and habitat: —The new species grows in humus-rich soil under broad-leaved forest at elevations of 700— 900 m. Phenology: —Flowering in mid-July; fruiting from August to October. Conservation status: —The populations of Chamaegastrodia guidongensis have only been found in Dongluo Village, with at most 100 m 2 distribution area and less than 50 mature individuals. It is worth mentioning that the size of populations declined than we observed in 2020, but the reason for the drift is unknown. As the populations are in the inaccessible habitat and no use of this species for traditional medicine were reported in local area. According to the Guidelines for using the IUCN Red List Categories and Criteria (2022), the new species should be temporarily assigned as ‘Critically Endangered’ (CR B2a & D) by its limited populations, localities and vulnerable habitats.