Epimedium muhuangense S.Z. He & Y. Y. Wang, 2017

Wang, Yue-Yun, Xu, Wen-Fen & He, Shun-Zhi, 2017, Epimedium muhuangense (Berberidaceae), a new species from China, Phytotaxa 319 (3), pp. 277-282 : 277-280

Epimedium muhuangense S.Z. He & Y. Y. Wang , sp. nov. Figs. 1 , 2A− F .

Type: — China. Guizhou, Yinjiang County, Muhuang Town, in shrubs on a hill, ca. 800 m a.s.l., 23 April 2010, Y. Y. Wang 100423 (holotype GZTM!).

Perennial herbs; flowering stems 25−40 cm tall, with two opposite leaves. Rhizomes short, 2−5 mm in diam.; fibrous roots numerous. Leaves basal and cauline, broadly ovate, often 5−7 cm long, 3−5 cm broad, apex acuminate, margin spinous-serrulate, base cordate with subequal lobes, adaxially dark green, abaxially pruinose, glabrous on both surfaces. Inflorescences paniculate, glabrous, 10−18 cm long, 25−50-flowered; pedicels ca. 1 cm long; bracts ovate, ca. 1.5 mm long. Outer sepals with dark purple stripes, margin hyaline, the out pair narrowly ovate, ca. 2 mm long, ca. 1.2 mm broad, the inner pair ovate, ca. 3 mm long, ca. 2 mm broad; inner sepals narrowly oblong, whitish, ca. 4.5 mm long, ca. 2 mm broad. Petals spurred, shorter than inner sepals, ca. 2 mm long, ca. 2 mm broad; spurs yellowish brown, straight; laminae yellow, ca. 1 mm long. Stamens prolonged, straight; anthers yellow, ca. 2 mm long, valved, valves revolute; filaments faintly yellow, ca. 1 mm long. Pistil ca. 3 mm long, style ca. 1.7 mm long. Capsule ca. 1 cm long, style ca. 3 mm long.

Distribution and Habitat:— Epimedium muhuangense is currently known only from its type locality, i.e. Muhuang Town, Yinjiang County, Guizhou, China. It grows in shrubs on a hill at elevations of 800−1000 m.

Phenology:—Flowering April to May, fruiting May to June.

Additional specimens examined (paratypes):— China. Guizhou:, Yinjiang County, Muhuang Town, 23 April 2010, Y.Y. Wang 100423 (GZTM).

Chromosome cytology:—The chromosomes of Epimedium muhuangense were examined by using conventional root-tip squashing method (voucher: Y.Y. Wang & S.Z. He 100423 (GZTM), Muhuang Town, Yinjiang County, Guizhou). The number is determined as 2 n = 12 (Fig. 3A). The karyotype is formulated as 2 n = 2 x = 6m (2sat) + 6sm (Fig. 3B) and is fairly symmetric with respect to chromosome size and chromosome type (here m = median centromeric chromosome with arm ratio of 1.0−1.7, sm = submedian centromeric chromosome with arm ratio of 1.7−3.0, and sat = satellited chromosome).

Pollen morphology:—Pollen morphology of Epimedium muhuangense (voucher: Y.Y. Wang & S.Z. He 100423 (GZTM), Muhuang Town, Yinjiang County, Guizhou) and its putative closest relative, E. elachyphyllum (voucher: T.L. Zhang & S.Z. He 92012 (GZTM), Ganlong Town, Songtao County, Guizhou), were observed under scanning electron microscope (SEM). The pollen in both species is spherical to prolate-spherical, tricolpate, with the colpus membrane being irregularly tuberculate and prominently spiny ( Fig. 4A, B ). The exine ornamentation of the pollen in both species is also very similar ( Fig. 4C, D ), being bar-reticulate and irregularly mesh-like. In the genus Epimedium , different exine ornamentations of pollen have been reported. They are bar-reticulate, irregularly reticulate or regularly reticulate ( Liang & Yan 1991, He & Guo 1997).

Notes:—The leaves of Epimedium species are usually compound with two to nine leaflets. In E. muhuangense , however, both basal and cauline leaves are simple. This feature is rather rare in the genus and, among the more than 40 species currently known in China, occurs merely in E. elachyphyllum , E. glandulosopilosum , E. muhuangense , E. simplicifolium , and E. zhushanense . In some other morphological characters, E. muhuangense is easily distinguishable from the other four unifoliolate species. Epimedium glandulosopilosum , E. simplicifolium and E. zhushanense are typically large-flowered taxa with the flowers over 1 cm in diameter and the spurs of petals far longer than the inner sepals. In contrast, E. muhuangense is a small-flowered species with the flowers less than 1 cm in diameter and the petals obviously smaller than the inner sepals.Although E. elachyphyllum is also a small-flowered species, it is distinct from E. muhuangense by having slender, long (vs. stout, short) rhizomes, a single, abaxially sparsely puberulous, simple leaf (vs. two glabrous, opposite leaves) on flowering stems, and racemose (vs. paniculate) inflorescences. A morphological comparison between E. elachyphyllum and E. muhuangense is given in Table 1.

Figures

FIGURE 1. Epimedium muhuangense. A. Habit. B. Outer sepal. C. Inner sepal. D. Petal. E. Flower. F. Mature stamen. G. Pistil. H. Capsule. Drawn from the holotype by X.L. Wu.

FIGURE 2. Epimedium muhuangense (A−F) and E. elachyphyllum (G−I). A. Habitat. B. Habit. C. Inflorescences and leaves. D. Flower. E. Plant with rhizome. F. Rhizome. G. Habit. H. Plant with rhizome. I. Rhizome.

FIGURE 4. SEM photographs of pollen in Epimedium muhuangense (A, C) and E. elachyphyllum (B, D). A, B. Pollen. C, D. Tectum.