Thismia jianfenglingensis Han Xu, H.J. Yang and S.Q. Fang, 2020

Xu, Han, Yang, Haijun, Lin, Mingxian, Corrales, Adriana, Hogan, James Aaron, Li, Yide & Fang, Suqin, 2020, Thismia jianfenglingensis (Thismiaceae), a new species of fairy lantern from Hainan Island, China, Phytotaxa 429 (2), pp. 179-185 : 180-183

Thismia jianfenglingensis Han Xu, H.J. Yang and S.Q. Fang , sp. nov. ( Figs. 1–3 ). 尖峰水玉杯

Diagnosis: — Thismia jianfenglingensis most closely resembles T. hongkongensis , but differs from it by having the perianth tube dark-red and cylindrical-urceolate (not pinkish-white obpyriform-urceolate), the outer perianth lobes are embedded in the dome (not separated from the dome), the connective apex is slightly concave (not bidentate), the lateral appendage of the connective is entire (not trilobed) and the stigma lobe is acute (not rounded).

Type:— CHINA. Hainan: Ledong County, Jianfengling National Nature Reserve, Wufengqu , 875 m, 18°43’41.0”N, 108°53’59.6”E, 20 June 2017, Han Xu 2017001 (holotype CANT; isotype IBSC)

Herbs, annual, without chlorophyll, myco-heterotrophic, with creeping vermiform and a ca. 1 mm thick rhizome. Stem white, unbranched, erect, and glabrous, ca. 3–4 cm long, 1.2 mm in diameter. Leaves 2–4, cauline, scale-like, whitish, elliptic lanceolate, entire, glabrous with blunt apex, 3–3.5 mm long, 1.5–2 mm wide. Flowers 2–3, subsessile, terminal, and arranged in a cincinnus. Bracts 3, 4–5 mm long, elliptic. Corolla actinomorphic, glabrous, deep orange-red in color. Floral tube urceolate with 12 ribs on its surface, 8 mm long, 7 mm in diameter. Perianth lobes numbering 6 in 2 whorls. Outer lobes linear, 3–3.5 mm long, 1 mm wide, apex oblique triangular, and lacking appendage. Inner lobes linear, 2.5–2.8 mm long, 1 mm wide, apex narrowly triangularly and extended into a filiform appendage. The lobes are imbricate without adhesion and form a loose dome with six holes in a woven manner; holes elliptic, 1.0– 1.2 mm wide, 1.8–2.0 mm high. Stamens 6, 3.5–4 mm long, anatropous, and hanging down at the upper inner margin of the perianth tube, dark-red; filaments free, 0.7 mm long; connective broad and flattened, laterally connate to form a tube, ca. 3 mm long, glabrous; apical end of the individual connective slightly concave, without any processes, and a slightly exceeding lateral appendage; lateral appendage large, nose-shaped, glabrous; each stamen with two separate thecae, 2 mm long, abaxial. Ovary inferior, obconical, 3 mm long, 3.5–4 mm in diameter; carpels 3, laterally connate to form one chamber; placenta columnar, free central, and trilobed to base; ovules numerous on each lobe of the placenta; style translucent red, cylindrical, and glabrous, 1.3–1.5 mm long, 0.5 mm in diameter; stigma 3, triangular, entire, translucent white, margin in a slightly reverse roll and bearing short prickles. Fruit and seeds not seen.

Phenology: —Fl. June–July.

Distribution and habitat:—This is the first documented report of Thismia and the type species, T.jianfenglingensis in Hainan Island. Thus, we presume the distribution of the species is limited to Jianfengling National Nature Reserve on Hainan Island, China. It grows in tropical montane rain forest at an elevation of about 875 m, although it is likely rare. This species was collected right next to an Engelhardia roxburghiana tree ( Juglandaceae ). The dominant tree species in the Jianfengling forest include of Livistona saribus ( Arecaceae ), Cryptocarya chinensis ( Lauraceae ), Alseodaphne hainanensis ( Lauraceae ), Lithocarpus fenzelianus ( Fagaceae ), Prismatomeris tetrandra ( Rubiaceae ) ( Xu et al. 2015).

Etymology:—The specific epithet for this species is related to place of its collection. Jianfengling is the name of the National Nature Reserve in Hainan, China.

Conservation status:—This species grows in the Jianfengling National Nature Reserve. In spite of many field surveys, only six individuals have been found. Taking into consideration the reproductive capacity of Thismia and the protected habitats where this species grows, more populations may be found in the future. However, in 2018, we visited the locality where the new species was collected but found no individuals. Therefore, we believe that the new species should be assigned the Vulnerable (VU) conservation status according to IUCN Red List criteria, indicating a population with a very restricted area of occupancy or number of locations such that it is prone to the effects of human activities or stochastic events within a very short time period in an uncertain future, and is thus capable of becoming Critically Endangered or even Extinct in a very short time period ( IUCN 2019).

Figures

FIGURE 1. Flowering plants of Thismia jianfenglingensis.

FIGURE 2. Thismia jianfenglingensis. A. Flowers; B. Transverse section of perianth tube; C. Lobes of perianth tube forming a net-cover or mitre; D. Inner lobes of perianth; E. Outer lobes of perianth; F. Stamens; G. Stamens 6 anatropous and hanging down at the upper inner margin of perianth tube; H–I. Stigma and its lobes; J. Longitudinal section of ovary; K–L. Transverse section of ovary.

FIGURE 3. Thismia jianfenglingensis. A. Flowering plant; B. Rhizome; C. Flowers; D. Lobes of perianth tube forming a net-cover or mitre; E. Longitudinal section of ovary; F. Stigma; G. Transverse section of ovary; H. Perianth tube; I. Stamens; J–L. Bracts.