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.

Significance of Fossil Pollen for Angiosperm History

Jan Muller
Annals of the Missouri Botanical Garden
Vol. 71, No. 2, Historical Perspectives of Angiosperm Evolution (1984), pp. 419-443
DOI: 10.2307/2399033
Stable URL: http://www.jstor.org/stable/2399033
Page Count: 25
  • Read Online (Free)
  • 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.
Significance of Fossil Pollen for Angiosperm History
Preview not available

Abstract

The significance of fossil pollen evidence for 139 families for understanding the evolutionary history of the angiosperms is discussed. Deficiencies in the fossil record and uncertainties in its interpretation are stressed. The transition from gymnospermous ancestors is as yet unknown. The earliest lower Cretaceous angiosperm pollen types, although few in number, indicate considerable taxonomic diversity. The succeeding progressive differentiation is clearly shown by the pollen as well as by the macrofossil record. The competitive replacement of ancient gymnosperms and ferns by angiosperms was largely completed in the Turonian. Strong differentiation takes place in the Maestrichtian and most higher taxonomic categories were present by the end of the Cretaceous. Differentiation at lower taxonomic levels continued in the Tertiary. Some taxa are discussed more in detail and are shown to have different timing and patterns of development. Dicotyledonous herbaceous types appear relatively late and, in the monocotyledons, the woody palms are a secondary development. In general, a positive correlation exists between advancement index and time of first appearance. Some evidence for evolution by gradual development, as well as by punctuated equilibria, is discussed.

Page Thumbnails

  • Thumbnail: Page 
[419]
    [419]
  • Thumbnail: Page 
420
    420
  • Thumbnail: Page 
421
    421
  • Thumbnail: Page 
422
    422
  • Thumbnail: Page 
423
    423
  • Thumbnail: Page 
424
    424
  • Thumbnail: Page 
425
    425
  • Thumbnail: Page 
426
    426
  • Thumbnail: Page 
427
    427
  • Thumbnail: Page 
428
    428
  • Thumbnail: Page 
429
    429
  • Thumbnail: Page 
430
    430
  • Thumbnail: Page 
431
    431
  • Thumbnail: Page 
432
    432
  • Thumbnail: Page 
433
    433
  • Thumbnail: Page 
434
    434
  • Thumbnail: Page 
435
    435
  • Thumbnail: Page 
436
    436
  • Thumbnail: Page 
437
    437
  • Thumbnail: Page 
438
    438
  • Thumbnail: Page 
439
    439
  • Thumbnail: Page 
440
    440
  • Thumbnail: Page 
441
    441
  • Thumbnail: Page 
442
    442
  • Thumbnail: Page 
443
    443