Liparis macrosepala Z.W. Wang, Y. Zhang & W.C. Huang, 2022

Wang, Zhengwei, Zhang, Yi, Zhang, Ze, Li, Xiaochen, Wu, Zhijin, Yan, Lan, Lu, Aixian, Xie, Chengzhi, Hu, Chao & Huang, Weichang, 2022, Liparis macrosepala (Orchidaceae), a new species from southwest China with its phylogenetic position, PhytoKeys 210, pp. 67-77 : 67

Liparis macrosepala Z.W. Wang, Y. Zhang & W.C. Huang sp. nov.

Figs 2 , 3 Chinese name: 大萼羊耳蒜

Type.

China. Yunnan Province (云南), Xishuangbanna (西双版纳), Mengla County (勐腊县) epiphyte on the tree trunk, 1620 m elev., 23Nov 2021, Zhengwei Wang, Xiaochen Li, Yu Zhang & Zhijin Wu, WZW04247 (holotype: CSH!)

Diagnosis.

Liparis macrosepala is characterised by the ovoid-fusiform, slightly compressed pseudobulbs with 4 or 5 alternate leaves on their apical half, these with slightly crispate margins, dorsal sepal ovate with cordate base, broadly elliptic, ca. 4 mm long, 2 callus-shaped and thickened folds, base with 2 oblong lobes on both sides, centrally with 1 thickened, concave callus, column with a single pair of arcuate wings.

Epiphytic herbs. Roots slender, flexuose. Pseudobulbs clustered, ovoid-fusiform, slightly compressed laterally, 1-2 × 0.5-1 cm, upper half with 4-5 widely spaced leaves. Leaf blade ovate-oblong, 1.8-2.3 × 0.8-1.2 cm, apex acuminate, base contracted into a short petiole, articulate, margins of their apical half slightly crispate. Peduncle 7-10 cm long, with several sterile bracts 2-5 mm long; raceme with 7-10 flowers arranged in zigzag manner. Floral bracts broadly ovate with cordate base, 2-3 × 1-1.5 mm, acute. Flowers greenish-orange; pedicel and ovary ca. 7 mm long. Dorsal sepal broadly ovate with cordate base, 3.2-5 × 3-3.6 mm, 1-veined, abaxially carinate, apex acute; lateral sepal oblong-ovate or ovate-lanceolate, 5-6 × ca. 0.6 mm long, abaxially slightly carinate. Petals narrowly linear, 3-4 × ca. 0.2 mm; lip elliptic, 2-3 × ca. 1 mm, apex apiculate, base bearing a bituberculate callus, then expanded on each side into a thickened, folded, rounded lobe, with 1 excavation with raised margins between the lobes. Column straight, ca. 2 mm long, with a pair of subtriangular, obtuse wings on each side near the middle and a ridge on the back of the column. Anther cap hemispherical, pale yellow; pollinia 4 in 2 pairs with one pollinium of each pair smaller than the other, waxy, brownish, with minute apical viscidium.

Phenology: Flowering in November-December.

Distribution and habitat.

It is found on tree trunks on a limestone ridge-top evergreen broad-leaved forest at an elevation of 1500-1700 m in Mengna County, Xishuangbanna Autonomous Prefecture, Yunnan Province, People’s Republic of China. The habitat presents a tropical monsoon climate.

Etymology.

The species epithet refers to the large and conspicuous dorsal sepal of the flower.

Taxonomic notes.

Liparis macrosepala differs from L. delicatula in its 4 to 5 leaves with slightly crispate margins on their apical half and single pair of wings on the column. Its entire, not Y-shaped petals and sessile lip (i.e. without a claw) easily distingush L. macrosepala from L. fissipetala . The dosal sepal of L. assamica is narrowly ovate-oblong, in contrast with the heart-shaped dorsal sepal of Liparis macrosepala . Liparis resupinata is distinguished from L. macrosepala by its 10-50-flowered raceme and the column with a single pair of broad wings, each with a retrorse thread. The main differences between these closely-related species, according to our phylogenetic analyses, are summarised in Table 2 .

Conservation assessment.

The new species was found in a ridge-top evergreen broad-leaved forest on a limestone mountain. Despite numerous surveys in the areas, only six mature individuals were found without fruits or evidence of cross-pollination.

This extremely small effective population occurs in a touristic zone which is a serious threat to the survival of the species. Consequently, the species can be assessed as Critically Endangered (CR, D), based on current information and following IUCN guidelines ( IUCN 2019).

Figures

Figure 2. Morphology of Liparis macrosepala. A plants in situ B flowering plant C pseudobulbs and leaves D inflorescence E flowers, front view F flowers, side view G perianth dissection H column from side I lip in oblique view J anther cap and pollinia. Photographs by Weichang Huang.

Figure 3. Liparis macrosepala A flower, front view B flower, side view C lip, side view D inflorescence E column, side view F lip and column, side view G lip, back view H lip, front view I flowering plant J pollinia and anther cap K perianth dissection L column and ovary, oblique view M ovary, transection. Drawn by Lan Yan.