Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Another perspective on Cytoevolution in Lobelioideae (Campanulaceae)

Helen M. Stace and S. H. James
American Journal of Botany
Vol. 83, No. 10 (Oct., 1996), pp. 1356-1364
Stable URL: http://www.jstor.org/stable/2446124
Page Count: 9
  • Read Online (Free)
  • Download ($12.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Another perspective on Cytoevolution in Lobelioideae (Campanulaceae)
Preview not available

Abstract

The Lobelioideae is a cosmopolitan group whose cytoevolution is discussed on a model of primitively high diploid chromosome numbers, in which x = 14 is relatively plesiomorphic and x = 21 may be even more plesiomorphic. This model is suggested from the high frequency of lobelioid genera with x = 14, the probably plesiomorphic condition of x = 17 in the sister group Campanuloideae (Campanulaceae), and the primitive x = 15 in Stylidiaceae (Campanulales). It contrasts with that for a primitive x = 7 and paleopolyploidy to higher chromosome numbers In our analysis, the genus Lobelia shows three broad cytoevolutionary groups, which probably have phylogenetic and infrageneric taxonomic significance: (1) woody diploids with x = 21 in Chile and woody diploids with x = 14 in Africa, Asia, and Hawaii; (2) herbaceous diploids with several series of dysploid chromosome numbers n = 19, 13, 12, 11, 10, 9, 8, 7, 6, mainly in Africa and Australia; (3) widespread and speciose herbaceous taxa based on a very derived n = 7, with recent frequent euploid rises (neopolyploidy) at or below the species level in subgenus Lobelia and allied or segregate genera Other woody and herbaceous lobeliad genera have comparable cytoevolutionary patterns. New chromosome counts for Australian Lobelia, Pratia, and Isotoma illustrate the last two cytoevolutionary groups.

Page Thumbnails

  • Thumbnail: Page 
1356
    1356
  • Thumbnail: Page 
1357
    1357
  • Thumbnail: Page 
1358
    1358
  • Thumbnail: Page 
1359
    1359
  • Thumbnail: Page 
1360
    1360
  • Thumbnail: Page 
1361
    1361
  • Thumbnail: Page 
1362
    1362
  • Thumbnail: Page 
1363
    1363
  • Thumbnail: Page 
1364
    1364