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Size distribution and coning behaviour of the Australian cycad Lepidozamia peroffskyana
Author(s) -
ORNDUFF ROBERT
Publication year - 1989
Publication title -
australian journal of ecology
Language(s) - English
Resource type - Journals
eISSN - 1442-9993
pISSN - 0307-692X
DOI - 10.1111/j.1442-9993.1989.tb01432.x
Subject(s) - biology , population , cycad , sex ratio , pollination , botany , horticulture , demography , pollen , sociology
Leaf numbers as an estimate of sexual maturity and presence of current and previous season's cones were determined for individuals sampled in two populations of Lepidozamia peroffskyana near Dorrigo and Sealy Lookout, New South Wales, Australia. Average leaf numbers of known males and females were not significantly different. Average leaf numbers of plants showing no evidence of coning were lower than for coning individuals, suggesting that both populations contain substantial numbers of immature plants. About half the plants in both populations were putatively mature, but only 12% of such individuals in the Dorrigo population bore current season's cones compared with 51% in the Lookout population; 28% of the Dorrigo plants and 5% of the Lookout plants showed evidence of prior coning. Thus, in each population, not all mature plants produce cones during a given reproductive episode. The proportion that does so appears to vary from year to year. Cone production by individuals of each sex appears to be separated by several‐year intervals. The few plants with current season's cones in the Dorrigo population prevented determining a phenotypic sex ratio there, but for the Lookout population it was not statistically different from 1:1 male:female. The weevil Tranes lyterioides was abundant on two male cones that were entering the pollination phase in the Lookout population, suggesting that it may be involved in the pollination of this cycad.