Comments on Greguss’s phylogenetical tree of plants

Recently (1955) I have published a new version of a phylogenetical tree of the Cormophyta, based on morphology, mainly ramification, leaf types, and sporangia. The concept is monophyletic but its basis is strewn with so many queries that the way is open to a number of different opinions. I add a corrected copy of my chart at the end of the present paper (fig. 2), so as to enable the reader to compare my views with those of Greguss (fig. 1). The difficulty lies of course in our still extremely scanty knowledge of the very oldest land plants and of whether one or several eventually more or less closely related algal groups have succeeded in conquering dry land and converting themselves into true land plants in which the greater part of the sporophyte developed into aerial shoots. As a matter of course the fact whether a progeny should be considered to have originated mono- or polyphyletically merely depends on the degree of relatedness of the ancestral group (s). Mono- and polyphyly may seem controversial when extreme cases are compared; actually they are connected by a series of gradual differences just like mono- and polytopy, analogy and homology, and the like, whose criteria may be found in the fields of time, space and/ or genealogical relationship.