Jackson Estuarine Laboratory

Ecological and genecological distinctions of a high intertidal dwarf form of Fucus distichus (L.) Powell in New England


Morphological, ecological, and genetic distinctions of a high intertidal, dwarf, non-tide pool member of the Fucus distichus (L.) Powell complex were assessed at an exposed site in southern Maine, U.S.A. Variation in plant stature from typical F. distichus ssp. edentatus (De la Pylaie) Powell to the dwarf form is continuous. On the other hand, measurements of reproductively mature plants collected throughout the eulittoral zone showed a bimodal pattern, i.e., there was a high frequency of dwarf forms (4–8 cm) and F. distichus ssp. edentatus (13–28 cm). The two forms have distinct reproductive phenologies: the dwarf plant exhibiting a unimodal reproductive maximum (fall), while F. distichus ssp. edentatus has pronounced bimodal reproductive maxima (spring and fall). Differences in stature and reproduction between the dwarf form and F. distichus ssp. edentatus were maintained when their respective progeny were grown under common environmental conditions. Thus, the differences are heritable rather than environmentally induced.

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Journal of Experimental Marine Biology and Ecology

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Copyright © 1983 Published by Elsevier B.V.