Microula roseiflora W.T. Yu, 2016

Yu, Wen-Tao, Yu, Yun, Shen, Jian-Guo & Guo, Qiong-Xia, 2016, Microula roseiflora (Boraginaceae), a new species from Qinghai-Tibetan Plateau, Phytotaxa 252 (2), pp. 149-153 : 149-153

Microula roseiflora W.T. Yu , sp. nov., Figs. 1–3 .

Affinis M. muliensi , a qua corollis roseis, appendicibus glabris, nuculis nigro-maculatis, foveolis dorsalibus majoribus 0.3–0.5 mm longis differt.

Type:— CHINA. Sichuan: Rangtang County, Chala hills, 26 km from Rangtang to Banma, ca. 3961 m, 32°19’06’’ N, 101°04’04’’ E, alpine meadows, 27 August 2014, W. T.Yu 2037 (holotype KUN, isotypes FJCIQ, PE).

Biennial herb. Stems ascending, branched from base, 5–17 cm tall, to 2.8 mm in diam., densely covered with white appressed trichomes (0.3–1.5 mm). Basal and lower stem leaves petiolate, lamina narrowly elliptic to spatulate; upper stem leaves sessile or with short petioles, to 8 mm long; lamina elliptic to ovate, 3–22 × 2–11 mm, adaxial surface densely covered with antrorse trichomes 0.4–1.0 mm long, abaxial surface covered with numerous trichomes (0.4–1.2 mm) on the veins and lamina; base attenuate, broadly cuneate to rounded, apex subacute, obtuse, to rounded. Terminal inflorescences crowded, 6–21 mm wide; inflorescences frondose-bracteose with upper bracts 5–9 mm; axillary inflorescences few flowered. Pedicel 1–3 mm, to 2–3 mm in fruit. Calyx ca. 2 mm, to 4 mm in fruit; lobes linear to narrowly triangular, densely covered with antrorse to spreading trichomes 0.3–0.8 mm long. Corolla hypocrateriform, pink, ca. 3–7 mm, glabrous; tube ca. 1–2 mm; faucal appendages pink, triangular-ovate, ca. 0.5 mm; limb ca. 3–5 mm in diam.; lobes subcircular, 0.5–0.8 mm long. Nutlets triangular-ovoid, ca. 1.9 × 1.2 mm, dark yellow-black spotted, with fine tubercles and shortly pubescent, ventrally and at base weakly keeled, dorsal pseudoaperture in median position, oblong, ca. 0.5 mm; areola minute, ventrobasal, shape triangular-ovate.

Distribution and habitat:— M. roseiflora is known from the Chala hills in the eastern Qinghai-Tibetan Plateau. The population found in the site consists of a few individuals growing in alpine meadows, at an elevation of ca. 4000 m ( Fig. 3 ).

Phenology: —Flowering in July–September; fruiting in Augusst–September.

Notes and Comparison:— Wang (1980b) recognized Microula sect. Schistocaryum by erect or ascending stems, presence of cauline leaves, lax inflorescences, ovoid nutlets, basal or median adaxial attachment scar, and the lack of membranous emergence inside the dorsal pseudoaperture margin. These characters can be found in M. roseiflora , so it is treated as a member of M. sect. Schistocaryum. In this section, M. muliensis W.T. Wang (1980b: 270) shares some characters with M. roseiflora , e.g. basally branching stems, elliptic to ovate leaves and ventrobasal nutlet attachment. However, the two species are easily distinguished from each other by corolla color, nutlet sculpture and other characters ( Table 1). For the nutlet sculpture, black spots on nutlets are rare in Microula . Besides M. roseiflora , M. leiocarpa W.T. Wang (1980b: 277) also shows black spots on nutlets. However, M. leiocarpa is known only from Deqin, Yunnan Province, which is ca. 800 km from the holotype locality of M. roseiflora . Moreover, the two species can easily be distinguished by stem trichomes, leaf shape, attachment scar position and several other characters ( Table 1).

The pink corolla ( Fig. 1A & B ), which is reported for the first time in Microula , is quite novel for the genus. It makes M. roseiflora different from any other congeneric species.

Etymology:— The specific epithet refers to its pink corolla of this new species.

Figures

FIGURE 1. Microula roseiflora (from the holotype locality). A. Habit. B. Flower. C. Nutlets. Photos by Wen-Tao Yu.

FIGURE 2. Microula roseiflora (from the holotype) A. Habit. B. Opened corolla. C. Pistil. D. Nutlet (abaxial view). E. Dorsal pseudoaperture. F. Nutlet (adaxial view). G. Attachment scar. (Drawn by Ling Wang).

FIGURE 3. Geographical distribution of Microula roseiflora, M.leiocarpa & M.muliensis.A. Distribution of M.roseiflora. B. Distribution of M. leiocarpa. C. Distribution of M. muliensis.