Inflorescences of Fargesia angustissima T.P. Yi and Yushania pauciramificans T.P. Yi (Poaceae, Bambusoideae) shed light on the taxonomy of the Sino-Himalayan alpine bamboos

Abstract

The taxonomy of the Sino-Himalayan alpine bamboos is controversial due to their complex evolutionary history and further complicated by the scarcity of inflorescence. Here, we supplement the description of the inflorescence of Fargesia angustissima T.P. Yi and Yushania pauciramificans T.P. Yi, which shed light on the taxonomy of Fargesia Franchet, Borinda Stapleton and Yushania Keng. F. angustissima has compressed inflorescence unilateral stretching out from reduced spathe, showing a transitional state between species with condensed inflorescence embraced by spathe-like bracts and species with open inflorescence without bracts. Considering that extensive gene flow existed between several clades of Fargesia found in recent studies, a broadly-defined Fargesia s. l. should be adopted. Meanwhile, the inflorescence of Y. pauciramificans has typical characteristics of Yushania, such as axilla with tuberculate glands, rachilla internodes ciliate and cylindrical florets, supporting the delimitation of Yushania.