A field, culture and cytological study of Porphyra gardneri (Smith & Hollenberg) comb. nov., (=Porphyrella gardneri Smith & Hollenberg), (Bangiales, Rhodophyta)
The transfer of Porphyrella gardneri Smith & Hollenberg to Porphyra gardneri (Smith & Hollenberg) comb. nov., is made on the basis of the absence of Erythrotrichia-like cross walls in α-spore formation, and the occurrence of divisions of the α-spore mother cells which are typical of the genus Porphyra. The morphological life history of Porphyra gardneri has been studied in the field and laboratory culture. A conchocelis phase is reported for the first time. The conchocelis has pit connections. β-spores and vegetative cells of the foliose thallus have four chromosomes. Photoperiod appears to be an important factor in the induction of (α- and β-spores. P. gardneri is always found growing epiphytically. It has been observed on fifteen Phaeophyceae (all Laminariales), and one Rhodophyceae.