Wednesday, October 13, 2021

[Botany • 2021] Cirsium taiwanense (Asteraceae) • A New Species of Cirsium (sect. Onotrophe, subsect. Australicirsium) from Taiwan

Cirsium taiwanense Y.H.Tseng & Chih Y.Chang, 

in Chang, Tzeng & Tseng, 2021.

A new species of CirsiumCirsium taiwanense Y.H.Tseng & Chih Y.Chang from central-northern Taiwan is reported in this article. This species is similar to C. hosokawae Kitam. in having a densely cobwebby abaxial leaf surface, but differs in its yellow (vs. vivid purplish red) corolla and the angle between the midrib and the lateral veins of the leaf, which is acute as opposed to nearly at a right angle in C. hosokawae. Cirsium taiwanense has 2n = 32 chromosomes, which is different from the other species in the Taiwanese subsect. Australicirsium Kitam. (2n = 34). An identification key to the Cirsium taxa of Taiwan is presented.

Keywords: Australicirsium Kitam., central-northern Taiwan, Cirsium, karyotype analysis, pollen morphology, 

Cirsium taiwanense Y.H.Tseng & Chih Y.Chang
 A habitat B habit C basal rosette D variations of rosette leaves E variations of cauline leaves F inflorescences G, H capitulum I floret I’ floret (pappus removed) J achenes.

Line drawings of Cirsium taiwanense Y.H.Tseng & Chih Y.Chang
  A habit B rosette leaf C cauline leaf D capitulum E floret E’ floret (pappus removed) F phyllaries G style branches H achene.

Cirsium taiwanense Y.H.Tseng & Chih Y.Chang, sp. nov.
Diagnosis: Differs from C. hosokawae in having a yellow corolla (vs. vivid purplish red corolla), a narrower angle between the midrib and lateral veins of the cauline leaves ((44–)52–73° vs. 82–90°), and usually more florets (101–135(–194) vs. 54–111) and phyllaries (90–127 vs. 68–109) per capitulum. Differs from C. arisanense by its nodding mature capitula (vs. erect), erect corolla lobes (vs. revolute), and a densely cobwebby abaxial leaf surface (vs. without cobwebby indumentum).

Distribution and habitat: Endemic species of Taiwan. Cirsium taiwanense grows in open areas between Querus forest and Abies forest at 1400–3400 m a.s.l. in central-northern Taiwan. Cirsium taiwanense usually grows at sunny sites. Common companion species are Artemisia morrisonensis Hayata (Compositae), Lilium formosanum Wallace (Liliaceae), Salix fulvopubescens Hayata (Salicaceae) and Rubus pectinellus Maxim. (Rosaceae).

Chinese name: Tai-wan-ji (臺灣薊).

 Chih-Yi Chang, Hsy-Yu Tzeng and Yen-Hsueh Tseng. 2021. Cirsium taiwanense (Compositae, Cirsium sect. Onotrophe, subsect. Australicirsium), A New Species from Taiwan. PhytoKeys. 183: 35-53. DOI: 10.3897/phytokeys.183.70119