Porphyra leucosticta along the Dutch Coast

Since Van Goor’s publication “Die Holländische Meeresalgen” appeared in 1923, the marine algae flora of Holland has not received much critical study. Since the war, however, the interest in this subject increased, and we have started a survey of our coast. During this work algae which had not been known to occur in our waters were found regularly. Probably this was because they were collected in localities which had never been investigated before. It may be assumed that some of the newly found species had settled here only a short time ago, while other species had probably been overlooked. Porphyra leucosticta e.g. is a species which has been washed ashore on our beaches since the days of old (i.a. 1844), but had never been recognised before. In the province of Zeeland this species now has been discovered as an autochthonic. There it forms a very characteristic association together with Monostroma wittrockii Bornet.