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 need an accessible version of this item please contact JSTOR User Support

Chromosome Cytology of Iridaceae-Patterns of Variation, Determination of Ancestral Base Numbers, and Modes of Karyotype Change

Peter Goldblatt and Masahiro Takei
Annals of the Missouri Botanical Garden
Vol. 84, No. 2 (1997), pp. 285-304
DOI: 10.2307/2400005
Stable URL: http://www.jstor.org/stable/2400005
Page Count: 20
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
If you need an accessible version of this item please contact JSTOR User Support
Chromosome Cytology of Iridaceae-Patterns of Variation, Determination of Ancestral Base Numbers, and Modes of Karyotype Change
Preview not available

Abstract

Against a background of 100 original counts for 95 species in 34 genera of Iridaceae, we review chromosome information for the entire family. Counts are now available for some 1008 of the estimated 1750 species of Iridaceae, and all but 5 of ca. 78 genera are known from at least one count. We suggest ancestral base numbers for all genera known cytologically and outline patterns of cytological variation within the subfamilies and tribes currently recognized. Polyploidy was evidently important in the early diversification of Iridaceae, and many genera have base numbers higher than x = 10. Neopolyploidy is important in Northern Hemisphere genera, especially Iris and Crocus, but has an unusually low frequency in Africa, the center of diversity for the family. Changes in basic number, frequent in a few genera, are evidently the result of dysploid reduction. In all but a few possible examples, correlated morphological specialization suggests that dysploid reduction is involved in stepwise change in base number. Major dysploid series are restricted to a few genera, including Romulea, the related Crocus, as well as Gladiolus and Lapeirousia (all Ixioideae), and Iris, Moraea, and Sisyrinchium (Iridoideae). All other genera have a single base number or limited variation evident in only one or two species. Patterns of chromosomal variation are particularly complex in Iris and Crocus and await detailed elucidation. More counts are needed in the Australian Patersonia, the South American-Australasian Orthrosanthus, and the neotropical tribe Mariceae, for all of which ancestral base number remains uncertain and patterns of cytological variation appear complex.

Page Thumbnails

  • Thumbnail: Page 
[285]
    [285]
  • Thumbnail: Page 
286
    286
  • Thumbnail: Page 
287
    287
  • Thumbnail: Page 
288
    288
  • Thumbnail: Page 
289
    289
  • Thumbnail: Page 
290
    290
  • Thumbnail: Page 
291
    291
  • Thumbnail: Page 
292
    292
  • Thumbnail: Page 
293
    293
  • Thumbnail: Page 
294
    294
  • Thumbnail: Page 
295
    295
  • Thumbnail: Page 
296
    296
  • Thumbnail: Page 
297
    297
  • Thumbnail: Page 
298
    298
  • Thumbnail: Page 
299
    299
  • Thumbnail: Page 
300
    300
  • Thumbnail: Page 
301
    301
  • Thumbnail: Page 
302
    302
  • Thumbnail: Page 
303
    303
  • Thumbnail: Page 
304
    304