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Pterygophora califomica Ruprecht (Laminariales, Phaeophyta) is a perennial brown alga often found in the upper subtidal zone of oceanic coastal sites of British Columbia, Canada. The phenology and age class distribution of P. californica was studied for over 2 yr at 3 study sites in Barkley Sound, British Columbia. Maximum elongation of stipes, apical blades, and sporophylls generally occurred from (Feb) Mar to Jun, and the minimum from Oct to Dec (Jan). Stipe elongation varies within and among sites (5.4 to 18.2 cm yr-l). Sporophylls made up 50 % of the total dry weight (minus holdfast) but the apical blade never exceeded 7 %. Stipe rings formed once a year, and this information was used to estimate age class distributions. At each study site there were very few young (< 2 yr) and old (> 9 yr) individuals. Based on age class distribution and other observations, the pattern of settlement and survival appears to be similar at the 3 sites. An existing population is decimated (probably by a combination of sea urchins and storms), followed by relatively high annual recruitment and survival rates for 3 to 4 yr. Subsequently there is little new recruitment until the adult plants once more disappear.

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