ECOLOGICAL NOTES ON PHYLLOSPADIX (POTAMOGETONACEAE) IN THE NORTHEAST PACIFIC

Three species of Phyllospadix were found from southern Oregon to Vancourver Island, Canada. Observations showed a zonal relationship between the three species. Phyllospadix serrulatus Ruprecht ex Aschers. grew from + 1.5 m to mean lower low water (MLLW); P. scouleri Hooker was intermediate (MLLW to ca. -1.5 m); P. torreyi Watson grew in water deeper than the other two species. Field observations and an examination of available herbarium material have shown that (1) P. scouleri flowers and forms fruits from southern Oregon to Sitka, Alaska, in April and June, respectively; (2) the phenology of P. serrulatus is identical from southern Oregon to Sitka, Alaska, and probably to the Chirikof Islands; (3) the phenology of P. torreyi is possibly similar to that of the other species. Seedlings and vegetative plants of Zostera marina L. were observed growing into a dense P. scouleri meadow on Whidbey Island, Washington. Sediment trapped by the Phyllospadix was ca. 8 cm deep, which allowed Zostera to invade. © 1979.