Petrocosmea duyunensis Sheng H.Tang, 2021

Tang, Sheng-Hu, Yang *, Jia-Wen, Li, Cong-Rui & Zhou, Qing, 2021, Petrocosmea duyunensis (Gesneriaceae), a new species from Guizhou, China, PhytoKeys 181, pp. 1-8 : 1

Petrocosmea duyunensis Sheng H.Tang sp. nov.

Figure 1

Type.

China Guizhou Province, Duyun County, Doupeng Mountain , 26.37 N, 107.37 E, about 1047 m a.s.l., 23 April 2021, Sheng-hu Tang 2021001 (Holotype: IBK!; Isotype: CSH!)

Diagnosis.

Petrocosmea duyunensis is most similar to P. leiandra in the shape of leaf blades and corolla limb, and in the indumentum of peduncles, calyx, and ovary. However, it differs from the latter in the following characteristics: apex of abaxial lip lobes of corolla acute and reflexed (vs. round and not reflexed), filaments densely glandular puberulent (vs. glabrous or sparsely pilose), pistil 4.7-5.8 mm long, included (vs. ca. 9 mm long, exserted), ovary ovoid (vs. narrowly ovoid), style distinctly curved, sparsely glandular puberulent, and 2.7-3.7 mm long (vs. slightly curved, glabrous, and ca. 7 mm long).

Description

. Perennial herbs; rhizomes short, 7-8 mm in length. Leaves 10-30, basal, crowded, with long petioles up to 5 cm, petioles densely glandular pilose and sparsely villous; leaf blades papery when dry, their outer blades ovate or suborbicular, 1.6-2.8 × 1.6-2.6 cm, the blade apex obtuse or rounded, base cordate, sometimes oblique, margin crenate, adaxial blade surface densely glandular pilose, abaxial blade surface densely pilose and sparsely glandular pilose, lateral veins adaxially impressed, abaxially conspicuous, 4-6 on either side of the midrib. Cymes 2-7, 1-3 flowers per cyme; peduncles 1.8-4.0 cm long, densely glandular pilose and sparsely villous; bracts 2, opposite, linear, 2-2.2 × 0.7-0.8 mm, sparsely puberulent outside, glabrous inside. Pedicels 1.0-2.5 cm long, densely glandular pilose and sparsely villous. Calyx zygomorphic, 5 lobes apex acuminate, densely pilose and sparsely glandular pilose outside, glabrous inside; adaxial calyx lib 3.9-4.2 mm in length, 3-lobed to below the middle, lobes narrowly triangular, 2.2-2.6 × 1.0-1.4 mm; abaxial calyx lib 2-lobed near the base, lobes oblong-triangular, 3.9-4.3 × 1.4-1.5 mm. Corolla blue-purple, 10.7-12.5 mm, glandular pubescent outside, glabrous inside; tube 4.6-5.4 mm, two yellow spots inside the tube beneath the anthers, throat violet, two white spots in the throat; adaxial corolla lip distinctly short, 1.0-2.0 mm in length, indistinctly 2-lobed, lobes 0.5-1.2 × 2.6-2.8 mm, reflexed slightly; abaxial corolla lip 6.8-8.1 mm, 3-lobed, lobes 2.6-3.0 × 4.6-7.1 mm, broadly ovate, with acute and reflexed apex. Stamens 2, free, adnate to the corolla tube at the base, included; filaments 1.5-2.0 mm in length, 0.5-0.7 mm in diameter, densely glandular puberulent, slightly curved near the middle; anthers ovate, 1.5-1.6 × 1.0-1.1 mm, dorsifixed; thecae parallel, dehiscing longitudinally. Staminodes 3, inconspicuous, adnate to the corolla tube at the base, glabrous. Pistil 4.7-5.8 mm long, included; ovary densely glandular pilose, ovoid, ca. 2.0 mm long, 1.2-1.6 mm in diameter; style 2.7-3.7 mm long, 0.2 mm in diameter, sparsely glandular puberulent below the middle, curved above the base at an angle approaching 90°; stigma capitate, 0.3 mm in diameter. Capsule 4.8-6.2 mm long, 1.9-2.0 mm in diameter, ovoid, dehiscing loculicidally to base, valves 2.

Phenology.

Flowering from April to May, fruiting in the wild is unknown, only capsules of the previous year were observed.

Etymology.

The new taxon is named after the type locality, Duyun county, China.

Vernacular name.

The Chinese name is "Dū Yún Shí Hú Dié” (都匀石蝴蝶).

Distribution and habitat.

To date, only a single population has been found in Doupeng mountain, Duyun county, Guizhou province, China. The plants were found growing on a moist shady cliff in a valley at an altitude of ca. 1047 m.a.s.l. The main companion species were Sloanea hemsleyana (Ito) Rehd. et Wils., Corylopsis multiflora Hance, Pittosporum glabratum Lindl., and Oreocharis elegantissima (H. Lév. & Vaniot) Mich. Möller & W.H. Chen.

Conservation status and IUCN Red List category.

One population with about 100 mature individuals was found at the type locality. The habitat is in a nature reserve protected by the local government. It is highly likely that more populations are present in the area. Before further investigations, this species should be assessed as "Data Deficient" (DD) according to the IUCN standards ( IUCN 2019).

Notes.

Although Petrocosmea duyunensis has a short adaxial corolla lip, the pistil is still included in the corolla. This is because the style is relatively short and distinctly curved. The plant possesses two free anthers. These characteristics differ from those of other Petrocosmea species. Morphologically, the species is similar to P. leiandra (Fig. 2 ), and detailed morphological comparisons are shown in Table 1 .

Figures

Figure 1. Petrocosmea duyunensis Sheng H. Tang sp. nov. A habitat B flowering plant, rhizome and fibrous roots (inset) C adaxial surface of leaf blade and indumentum (inset) D abaxial surface of leaf blade E, F flowers in front view G flower in side view H flower in back view I, J dissected corolla, stamens and pistil with corolla removed (inset) K stamens and anther (inset) L pistil with abaxial calyx lobes, and adaxial lobes removed M capsules of previous year. (Photographed by Sheng-Hu Tang).

Figure 2. Petrocosmea leiandra (W. T. Wang) Z. J. Qiu A habitat B flowering plant C abaxial surface of leaf blade D, E flower in front view F flower in side view G flower in top view H flower in back view I dissected corolla J stamens K pistil with calyx removed L capsules of previous year. (Photographed by Sheng-Hu Tang).