STUDIES ON HEPATICAE, LIV-LVIII. KURZIA V. MART. [MICROLEPIDOZIA (SPR.) JOERG.], MEGALEMBIDIUM SCHUST., PSILOCLADA MITT., DRUCELLA HODGS. AND ISOLEMBIDIUM SCHUST.

Abstract

  The studies reported on here represent a summation of what I have learned about the complex of genera including Kurzia, Megalembidium, Psiloclada, Drucella, and Isolembidium. These genera belong to a complex in which transverse to succubous leaves are the norm (the monotypic genera Megalembidium and Drucella forming exceptions), the cuticle is often roughened, Microlepidozia branches occur (the monotypes Psiloclada and Drucella forming exceptions), and in which there is a marked tendency for oil-body loss, partial or total. Most members are further characterized by a tendency towards formation of thick-walled, rigid, and relatively small cells. Members of the Kurzia-Psiloclada pair are closely allied to each other; Megalembidium is much less closely affiliated and, indeed, its relationships remain obscure. Equally isolated and, indeed, unique are Drucella and Isolembidium. Our understanding of this complex remains very imperfect; I had once hoped to produce a monograph of the entire group and the mass of data here presented has accumulated over 17 years (from 1962 to 1979) Investigations of branching patterns, stem and sporophyte anatomy, reported on fully here, may eventually point the way to a clear understanding of the whole complex. At this point, however, monographic treatment is impossible; any such attempt, today, would only result in a pseudomonograph. However, I have made a very detailed study of the taxa present in two areas: Australasia and North America. For these areas I can include a treatment of almost all the taxa.

  Field work forming the background of these studies was pursued in North America (1942-1979), Japan (1974), New Zealand (1961-62, 1967), New Guinea (1967), Tasmania (1962), South America (1961, 1969-70, 1976, 1979), Europe (1978 and earlier), Fiji (1962, 1967), Tahiti (1967) and elsewhere. Long residence, in New Zealand especially, permitted detailed investigation of critical taxa through use of masses of fertile material and allowed investigations of oil-body presence or absence, dispersal and form. As a consequence, I have been able to investigate in some detail 30 taxa at the species and infraspecific level; keys to these taxa are also included. Of the 33 species listed by Grolle for Kurzia (1964), all but a handful have been studied. All species of the other genera have been studied and are herein illustrated.