Mitreola bullata Y. S. Chen & J. J. Liao, 2021

Liao, Jun-Jie & Chen, You-Shen, 2021, Mitreola bullata sp. nov. (Loganiaceae), a new species from Yunnan, China, Phytotaxa 487 (2), pp. 181-184 : 181-183

Mitreola bullata Y. S. Chen & J. J. Liao , sp. nov. (Fig. 1)

Type:— CHINA. Yunnan province: Yuanyang county, Daping town, Shangxinya , on shady limestone cliffs by a stream, 22°55′14.29”N, 103°5′56.53”E, 1526 m, 1 April 2020, Y. S . Chen et al. YY1118 (holotype IBSC; isotypes KUN, PE) .

Perennial herb, 3.0– 8.5 cm tall. Stem terete, erect, short, simple or branched at base, old stem leaf traces obvious; internodes 3.0–6.0 mm. Leaves opposite, often clustered at the stem or branch apex, petiolate; petioles 1.0–2.6(–3.5) cm long, purplish red or green, densely pilose; leaf blade bullate, thickly papery when dry, elliptic or long elliptic, 1.8–5.2(–8.5) cm long, 0.8–1.7(–3.2) cm wide, apex acute or obtuse, base cuneate or rounded, margin entire, densely pilose on both surface, pilose along margin and nerves beneath; lateral veins 7–10 pairs, sunken above, proliferous beneath, veins in abaxial surface purplish red; stipules triangular, interpetiolar, ca. 1.0 mm long. Inflorescence dichasium, terminal and axillary, peduncle up to 4.0 cm long, purplish-green, sparsely pilose or glabrescent, usually more than 10 flowered; bracts lanceolate 1.5–4.0 mm long. Pedicel 1.0–2.0 mm long. Calyx 5, glabrous, purplish red, long-triangular, base conate. Corolla urceolate, light purple, ca. 3 mm long, lobes 5, broad ovate, 1.3–1.5 mm long, with tubes almost isometric, glabrous except have a ring of long hairs at throat. Stamens 5, nearly inserted at the middle of corolla tube, filaments ca. 0.5 mm long, anthers broad ovate, ca. 0.4 mm long. Ovaries semi-inferior, two carpels, distinct; style ca. 0.3 mm long, free at base, stigma capitate. Capsules split near the middle, with two erect horns, ca. 3.5 mm long, ca. 3.5 mm wide, sepals persistent at base.

Phenology: Flowering in from March to April, fruiting from May to June.

Distribution and habitat: — Mitreola bullata is currently known only from one locality in Yuanyang County, Yunnan Province, China. It grows on shady limestone cliffs by a stream at the elevation of ca. 1526 m.

FIGUEW 1. Mitreola bullata A–B. Habitat; C. Plant; D. Inflorescence; E. Corolla opened; F. Leaf blades; G. Fruit. (Photos A–D took by You-Sheng CHEN from Y. S. Chen et al. YY1118, Photos E–G took by Jun-Jie LIAO, E from Y. S. Chen et al. YY1118, F–G from Y. S. Chen et al. YY1054).

Etymology:—The specific epithet refers to the bullate leaves, which is a very rare character in Mitreola . Chinese name:

泡叶度fiff (Pao Ye Du Liang Cao).

Additional specimens (paratypes) examined: — CHINA. Yunnan province, Yuanyang county, Daping town, Shangxinya , on the shady limestone cliff by a stream, 1526 m, 15 June 2020, Y. S . Chen et al. YY1054 ( IBSC) .

Notes: — Mitreola bullata is most similar to M. yangchunensis Q. X. Ma, H. G. Ye & F. W. Xing (2010: 42) in its stems terete, stamens nearly inserted at the middle of corolla tube, capsules split near the middle and with two erect horns, but differs by its low height, leaf blades bullate and densely pilose on both surface, petiole longer and purple or green, veins in abaxial surface purple, calyces glabrous and purplish red (see Table 1 ).

Conservation status: — During our one year’s fieldwork in southeastern Yunnan, Mitreola bullata is currently found only from the type locality with no more than 100 individuals in Yuanyang County. It is easily disturbed because its habitat is close to a town and farmland. It is considered to be Critically Endangered ( CR B1 , 2 a; C2 a) because of its small size of only one population, which is vulnerable to human disturbance ( IUCN Standards and Petitions Subcommittee 2019) .