Revision of the Lichens of the Netherlands. II. Physciaceae

In my paper on Parmeliaceae (in Blumea, vol. 6, 1947) some remarks have been made concerning the taxa below the rank of species (p. 3—4), one of them being the statement that I was to try to hold an intermediate course between those authors accepting multitudes of varieties and forms, and others abandoning them all. In the eyes of both I may have failed. In the present paper I am going to alienate myself still farther from the former group of authors in reducing varieties to forms and doing away with many other forms. Although in a way this contradicts my inclination towards a meticulous classification in my former paper, it should be borne in mind that not all genera in lichenology can be treated alike. I still believe in varieties and forms — considering e.g. Parmelia physodes very good illustration — but on the other hand I am well aware now that in following Hillmann, whom I shall always gratefully remember for his kind help during the early days of my lichenological training, I have been decidedly all too punctilious.