With Vol. VI this comprehensive work is brought to its final completion. It includes, first, a detailed account of the order Marchantiales. Initially the group is given a taxonomically/phylogenetically oriented treatment of the intricate anatomy and morphology. The Marchantiales include not only that bane of elementary botany students, Marchantia polymorpha, but a whole range of extraordinary plants, with diverse adaptations to a land environment – often one that seems highly inimical to survival of such nonvascular organisms with an aquatic sexual reproduction. The highly interesting ecology and reproductive behavior of the various taxa are explored in considerable detail.
For the Marchantiales the author provides not only illustrations of the taxonomically important anatomical and cytological details but a wide range of drawings which are unique in giving the student a clear representation of what the living plant looks like.
Lastly, the volume includes a detailed treatment of the Anthocerotophyta, a group with a limited number of genera and species in a single class, the Anthocerotales. This group has had an enormous literature devoted to it and its phylogenetic orientation remains a bone of contention. This literature is reviewed in detail and the author presents his own ideas at some length.
The Marchantiales and Anthocerotales, although including a limited number of genera and species, include some of the most difficult and complex groups of Bryophytes. For genera like Riccia, with its countless species, and Anthoceros, s. lat., species limits are often not clearly established. Here the controversial details are given an airing and the author's conclusions – usually based on study of living plants – are given.
In this volume, as in Vol. V, over 140 plates (composite "figures") are presented, virtually all drawn by the author, often from living plants.
With the completion of this work, the student is now provided with a detailed treatment of all of the 500+ taxa of hepatics and anthocerotes found east of the 100th meridian. The work summarizes research carried on for over 45 years and the illustrations serve to enhance one of the most detailed accounts of any group of nonvascular plants. The volume concludes with an exhaustive bibliography which supplements the one found on pp. 11-115 in Vol. I.