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.

Periodicity of Seedling Emergence and Achene Survival in Some Species of Carduus, Cirsium and Onopordum

H. A. Roberts and R. J. Chancellor
Journal of Applied Ecology
Vol. 16, No. 2 (Aug., 1979), pp. 641-647
DOI: 10.2307/2402538
Stable URL: http://www.jstor.org/stable/2402538
Page Count: 7
  • Read Online (Free)
  • Download ($18.00)
  • 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.
Periodicity of Seedling Emergence and Achene Survival in Some Species of Carduus, Cirsium and Onopordum
Preview not available

Abstract

(1) Achenes of seven species of Carduus, Cirsium and Onopordum were collected in August-September and mixed with the top 2.5 or 7.5 cm of soil which was then periodically disturbed during 3 or more years. (2) Between 0 and 40% of the achenes produced seedlings in the autumn of sowing. There was wide variation between sowings of the same species in different years, as well as between species. (3) Subsequent seedling emergence was mainly in March-April (Cirsium eriophorum, C. palustre, C. vulgare), April (Carduus acanthoides, C. nutans) or April-May (Cirsium arvense). Onopordum acanthium showed a contrasting pattern; most seedlings appeared in July-September, with small numbers in other months. (4) More than 90% of all seedlings of Cirsium and Carduus spp. that emerged did so within a year after sowing. There were few or none after the second year and very few dormant achenes remained after 5 years. (5) Only about half the achenes of O. acanthium mixed with 7.5 cm of soil produced seedlings in the first 16 months. Seedlings continued to appear subsequently and up to 8% of the achenes sown were still dormant and viable after 5 years.

Page Thumbnails

  • Thumbnail: Page 
641
    641
  • Thumbnail: Page 
642
    642
  • Thumbnail: Page 
643
    643
  • Thumbnail: Page 
644
    644
  • Thumbnail: Page 
645
    645
  • Thumbnail: Page 
646
    646
  • Thumbnail: Page 
647
    647