Petrocosmea tsaii Y.H.Tan & JianW.Li, 2019

Yang, Bin, Ding, Hong-Bo, Fu, Kai-Cong, Yuan, Yi-Kai, Yang, Han-Yu, Li, Jian-Wu, Zhang, Li-Xia & Tan, Yun-Hong, 2019, Four new species of Gesneriaceae from Yunnan, Southwest China, PhytoKeys 130, pp. 183-203 : 183

2. Petrocosmea tsaii Y.H.Tan & JianW.Li sp. nov. Figures 3 , 4

Diagnosis.

Petrocosmea tsaii is similar to P. kerrii var. kerrii and P. menglianensis in having elliptic leaf blade, oblique and rounded leaf base, acute leaf apex, ellipsoid anthers with brevirostrate apex; but it can be easily distinguished from the two similar taxa by its bluish purple corolla (vs. white) and much longer inflorescences. Petrocosmea tsaii also differs from P. kerrii var. kerrii by having actinomorphic calyx (vs. zygomorphic), and differs from P. menglianensis by its leaf blade abaxially densely villous (vs. pubescent along midrib and lateral veins).

Type.

CHINA. Yunnan Province: Mengla county, Menglun, Mengxing, 21°49'N, 101°23'E, a.s.l. 1200 m, 13 Sep. 2016, Jian-Wu Li 4577 (holotype: HITBC!).

Description.

Perennial herb with short rhizomatous stem. Leaves 8-15, in basal rosette; inner leaves with petioles short or absent, ovate or suborbicular; outer leaves with long petioles, elliptic or ovate to widely ovate; 1.5-10.5 × 1.2-8.2 cm, apex acute to rounded, base rounded to subcordate, sometimes oblique, margin crenate, densely villous on abaxial surfaces, sparsely pubescent to puberulous on adaxial surface; lateral veins 4-10 on either side of midrib, adaxially impressed, abaxially conspicuous; petioles up to 10 cm long, densely white villous. Inflorescences 6.0-14.5 cm long; Peduncles 3.5-11.0 cm long, 2.0-2.5 mm in diam., densely villous and with glandular hairs; bracts 2-3, ovate to broadly ovate, or somewhat leaf like, with 4-5 lateral veins on side, ovate-elliptic, 8-19 × 6-18 mm; cymes usually 3 –6(– 8)-flowered, hypopodium 0.5-3.5 cm, pedicels 1.2-2.3 cm, villous and with glandular hairs; bracteoles 2, opposite, linear-lanceolate, 3.5-8.3 × 1.5-2 mm. Calyx actinomorphic, equally divided into 5 lobes from base, lobes linear-lanceolate, 6-7 × 1-1.5 mm, internally sparsely with glandular hairs, externally villous and with glandular hairs, margin with 1-3 linear teeth above middle. Corolla 10.5-12 mm long, externally sparsely puberulous to glabrous, internally glabrous; tube 4-4.5 mm; throat dark bluish purple; adaxial lip ca. 7-9 × 10-12 mm, indistinctly 2-lobed with the two lobes reflexed, lobes semi-orbicular, with rounded apex and entire margin, base white; abaxial lip ca. 16-20 × 9-11 mm, 3-lobed to the middle, lobes semi-orbicular, with rounded to obtuse apex, bluish purple. Stamens 2, 4-4.5 mm long, adnate to the base of the corolla tube; anthers adnate face to face; filaments 1.5-2 mm long, with short glandular hairs near base; anther ovoid to ellipsoid, 3-3.5 mm long, with brown capitate-glandular hairs, dorsifixed, apex brevirostrate. Staminodes 2-3, ca. 1 mm, adnate to the corolla tube at the base, linear, glabrous. Pistil 11-12 mm; ovary 3-3.5 mm long, narrowly ovoid, sparsely pubescent and with yellow glandular hairs; style 7.5-9 mm, sparsely with yellow glandular hairs at base, upper part glabrous; stigma capitate. Fruit a short capsule, 10-12 mm long.

Etymology.

The specific epithet commemorates the late Prof. Cai Xitao (Tsai Hse-Tao), who was the founder of Xishuangbanna Tropical Botanical Garden (XTBG) and devoted all his life to the study of Chinese plants.

Vernacular name.

Chinese mandarin: Cai Shi Shi Hu Die (蔡氏石蝴蝶)

Phenology.

Flowering September-October and fruiting October-November.

Distribution and habitat.

The species grows on moist rock faces in limestone forests, Mengla County, Yunnan, China.

Conservation status.

Due to insufficient field surveys so far, very few details about its natural distribution and population status are currently known. The lack of sufficient data does not allow a risk evaluation and the species can be regarded at present as Data Deficient (DD) according to the IUCN Red List Categories ( IUCN 2012).

Note.

A comparison of the diagnostic characters of the new species and P. kerrii var. kerrii , P. menglianensis is given in Table 2 .

Figures

Figure 3. Petrocosmea tsaii Y. H. Tan & JianW. Li, sp. nov. A, B Habit C leaves D, E inflorescence F flower in front view G flower in back view H flower in side view I dissected flower J calyx in abaxial view K pistil L stamens. Photographed by J. W. Li, Y. H. Tan & H. B. Ding.

Figure 4. Petrocosmea tsaii Y. H. Tan & JianW. Li, sp. nov. A Habit B adaxial Leaf surface indumentum C corolla (Dissected) D pedicel with bracteoles, calyx and pistil E pistil F stamens. Drawn by Zhengmeng Yang.