首页   按字顺浏览 期刊浏览 卷期浏览 Pollen morphology and taxonomy of Eurasiatic species of the genusBuxus(Buxaceae)
Pollen morphology and taxonomy of Eurasiatic species of the genusBuxus(Buxaceae)

 

作者: Paul Brückner,  

 

期刊: Grana  (Taylor Available online 1993)
卷期: Volume 32, issue 2  

页码: 65-78

 

ISSN:0017-3134

 

年代: 1993

 

DOI:10.1080/00173139309429456

 

出版商: Taylor & Francis Group

 

数据来源: Taylor

 

摘要:

Pollen morphology of 33 Eurasiatic taxa of the genusBuxuswas investigated by light and scanning electron microscope. The pollen is generally pantoporate. In comparison with the American and African sections of the genus, in which evolutionary lines from 3-colporatc to pantoporate conditions are found, the Eurasiatic species are more derived. A tendency to diminish pore size (Ø from 6.0 to 0.5–1.0 μm) as well as to increase number of apertures (from 12 up to 34) is correlated with geography, ranging from tropical SE Asia to the north and west parts of the area. Based on SEM details of exine 6 pollen types are described. Quantitative characters are listed, and LM and SEM illustrations are given. Pollen characters and evolutionary trends are discussed. Supposed evolutionary trends in pollen morphology of EurasiaticBuxusare (primitive → derived character state): Pori round → irregularly shaped, distinct → indistinct margin, large → small, few → many. Exine reticulate → reticulate-verrucoid → verrucoid-pilate. Reticulum continuous → interrupted. Surface of muri smooth → spinulate. The results confirm a close relation between the Eurasiatic sectionsBuxusandEugeniobuxusHatusima. The subsectionsSessilifloraeMathou andPedicellataeMathou of sectionBuxusare to be rejected. SE Asia is considered to be centre of diversity of the EurasiaticBuxusspecies. Beside Central America and southern Africa it is one of the evolutionary centres of the genusBuxus.

 

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