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.

Floral Display in Phlox and Geranium: Adaptive Aspects

Mary F. Willson, Linda J. Miller and Beverly J. Rathcke
Evolution
Vol. 33, No. 1, Part 1 (Mar., 1979), pp. 52-63
DOI: 10.2307/2407365
Stable URL: http://www.jstor.org/stable/2407365
Page Count: 12
  • Read Online (Free)
  • Download ($4.00)
  • 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.
Floral Display in Phlox and Geranium: Adaptive Aspects
Preview not available

Abstract

Both Geranium maculatum and Phlox divaricata are self-compatible, the flowers lasting 4-6 days typically; geranium is protandrous. Large inflorescences produced more seeds, but the seed production per flower varied little with number of flowers per stem-decreasing slightly for geranium, and increasing slightly for phlox at one site. Very small numbers of flowers per stem had a higher probability of failing to make any seeds at all. The frequency distributions of number of flowers per stem and cluster size were both skewed toward the smaller sizes. The modal number of flowers per stem for phlox fell close to 'optima' predicted from the data on flowers per stem, cluster size, and seed production per flower in a model that maximized seed production per individual (or cluster). However, modal cluster sizes were much smaller than the predicted optima, probably because of environmental heterogeneity-microsite and temporal differences. No effect of between-plant distances on seed set was observed. We know of no other study that attempts to relate the entire floral display of plants to any index of fitness and present these preliminary results in hopes of stimulating more consideration of such matters.

Page Thumbnails

  • Thumbnail: Page 
52
    52
  • Thumbnail: Page 
53
    53
  • Thumbnail: Page 
54
    54
  • Thumbnail: Page 
55
    55
  • Thumbnail: Page 
56
    56
  • Thumbnail: Page 
57
    57
  • Thumbnail: Page 
58
    58
  • Thumbnail: Page 
59
    59
  • Thumbnail: Page 
60
    60
  • Thumbnail: Page 
61
    61
  • Thumbnail: Page 
62
    62
  • Thumbnail: Page 
63
    63