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The Population Age Structure of Spotted Knapweed (Centaurea maculosa) in Montana

Published online by Cambridge University Press:  12 June 2017

Keith W. Boggs  and
Jim M. Story
Keith W. Boggs
Affiliation:
Western Agric. Res. Ctr., Corvallis, MT 59828
Jim M. Story
Affiliation:
Western Agric. Res. Ctr., Corvallis, MT 59828
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Abstract

Spotted knapweed (Centaurea maculosa Lam. # CENMA) communities were sampled to determine the relationship between age and the number of root rings, and the population age structure. Spotted knapweed taproots add one ring of secondary xylem annually. In 1984, populations were expanding with high densities of individuals in the early age classes, followed by a steady decline in the older classes. In 1985, the majority of the individuals in knapweed populations were in the older age classes. This change in the population age structure was attributed to high mortality among the young age classes due to a drought in 1985. The maximum age class at the sites ranged from 5 to 9 yr. The percentage of plants with floral stalks increased with age to a peak of 75% in the fifth year in 1984 and in the seventh year in 1985.

Keywords

Xylem root ringsroot ringsvegetative rosettesflowering agelife spanage of herbaceous dicotyledonCENMA
Type
Weed Biology and Ecology
Information
Weed Science , Volume 35 , Issue 2 , March 1987 , pp. 194 - 198
Copyright
Copyright © 1987 by the Weed Science Society of America 

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References

Literature Cited

1. Fayle, D. C. 1975. Distribution of radial growth during the development of red pine root systems. Can. J. For. Res. 5:608–625.Google Scholar
2. Hitchcock, C. H. and Cronquist, A. 1978. Flora of the Pacific Northwest. Univ. of Washington Press, Seattle and London. 730 pp.Google Scholar
3. Kerster, H. W. 1968. Population age structure in the prairie forb, Liatris aspera . Bioscience 18:430–432.Google Scholar
4. Levin, D. A. 1973. The age structure of a hybrid swarm in Liatris (Compositae). Evolution 27:532–535.Google Scholar
5. Maddox, D. M. 1979. The knapweeds: their economics and biological control in the western states, U.S.A. Rangelands 1:139–141.Google Scholar
6. Molisch, H. 1938. The Longevity of Plants. Edmund H. Fulling, New York. 226 pp.Google Scholar
7. Muir, A. D. and Majak, W. 1983. Allelopathic potential of diffuse knapweed (Centaurea diffusa) extracts. Can. J. Plant Sci. 63:989–996.Google Scholar
8. Reynolds, E. R.C. 1983. The development of root systems analyzed by growth rings. Plant Soil 71:167–170.Google Scholar
9. Schirman, R. 1981. Seed production and spring seedling establishment of diffuse and spotted knapweed. J. Range Manage. 34:45–47.Google Scholar
10. Story, J. M. 1977. Biology of spotted knapweed in Montana. Pages 31–38 in Proceedings of the Knapweed Symposium. Kamloops, British Columbia.Google Scholar
11. Story, J. M. and Nowierski, R. M. 1984. Increase and dispersal of Urophora affinis (Diptera: Tephritidae) on spotted knapweed in western Montana. Environ. Entomol. 13:1151–1156.Google Scholar
12. Strang, R. M., Lindsay, K. M., and Price, R. S. 1979. Knapweeds: British Columbia's undesirable aliens. Rangelands 1:141–143.Google Scholar
13. Torrey, J. G. and Wallace, W. 1975. Distribution of secondary thickening in tree root systems. Pages 197–217 in Torrey, J. G. and Clarkson, D. T., eds. The Development and Function of Roots. Academic Press, London, New York, San Francisco.Google Scholar
14. Watson, A. K. and Renney, A. J. 1974. The biology of Canadian weeds. Centaurea diffusa and C. maculosa . Can. J. Plant Sci. 54:687–701.Google Scholar