Saturday, February 20, 2016

[Botany • 2015] Rhododendron xiaoxueshanense • A New Species of Rhododendron (Ericaceae) from Shangri-La, NW Yunnan, China

 FIGURE 1. Rhododendron xiaoxueshanense R.l. Liao and Y.P. Ma (A, B, C, D) and R. trichostomum Franch(E, F, G, H ).
A. & E. Habitat.— B. & F. Inflorescences and leaves.— C. & G. Flowers.


Rhododendron Linnaeus (1753: 392) exhibits great diversity and roughly 1,025 species are prized in the temperate parts of the world for their horticultural value (Chamberlain et al. 1996). There are approximately 680 species in six subgenera in China, of which more than 400 are endemic (Fang & Min 1995). However, the number of Rhododendron species known is increasing, with many new species being described after the publishing of Flora of China (Fang et al. 2005, Chen et al. 2012, Mao et al. 2013, Ma et al. 2015, Mao & Bhaumik 2015).

Xiaoxueshan Mountain lies in the Northeast of Shangri-la, NW Yunnan, China. In 1995, one of our co-authors Mr. Jens Neilsen visited Xiaoxueshan Mountain and noticed an unknown Rhododendron species growing on steep cliff close to the main road. This species is similar to R. trichostomum Franchet (1895: 396), but differs in leaf, inflorescence and fruit characters (Fig. 1). However, no detailed observation was carried out and no specimens were collected at that time. In June 2013, a field investigation was conducted, aiming to examine and fully describe this new species during its flowering period, and its status as a distinct new species was confirmed.


FIGURE 1. Rhododendron xiaoxueshanense (A, B, C, D) and R. trichostomum (E, F, G, H ). — A. & E. Habitat.— B. & F. Inflorescences and leaves.— C. & G. Flowers.— D. & H. Fruits.

Taxonomic treatment

Rhododendron xiaoxueshanense R.l. Liao and Y.P. Ma, sp. nov. ( Fig. 2)

Rhododendron xiaoxueshanense resembles R. trichostomum, but differs from the latter in having elliptic leaves in maturity, much longer pedicels  (4.57±0.16  mm  vs.  1.77±0.07  mm)  but  a  shorter  calyx  (2.67±0.08  mm  vs.  5.76±0.08  mm),  a  white  corolla  and  a  2–6 flowered inflorescence (Table 1).

Type:— CHINA. Yunnan: Xiaoxuehsan Mountain, Shangri-La county. ca. 3500 m, 99°45′09.44′′E, 28°22′10.95′′N, June 2013, R.L. Liao& Y.P. Ma, SL1306002 (holotype: KUN!; isotype: KUN!)

Distribution  and  ecology:— To  date, Rhododendron  xiaoxueshanense  is  known  only  from  the  type  locality  at Xiaoxueshan Mountain (99°45′09.44′′E, 28°22′10.95′′N), in Shangri-La county, NW Yunnan, China (Fig. 3). The plants have been found on rocks and cliff ledges at elevation of ca. 3500m (Fig. 1a).

Etymology:— The specific epithet refers to the site (Xiaoxueshan Mountain) where the new species was discovered and collected.

Rongli Liao, Dan Xue, Jens Neilsen, Jihua Wang and Yongpeng Ma. 2015. A New Species of Rhododendron (Ericaceae) from Shangri-La, NW Yunnan, China.  Phytotaxa. 238(3): 293–297. DOI: 10.11646/phytotaxa.238.3.10