MAR 1963 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



11(1):1-172 



INTRODUCTION 



The concept of this work first became a reality twenty years ago at The New 

 York Botanical Garden, where several Marshall A. Howe Fellowships helped to 

 make possible the series of taxonomic studies begun at that time on the Lejeu- 

 neaceae and other families. With the assistance of two National Science Founda- 

 tion Research Grants since July 1956, it has been possible to continue the work 

 more intensively and extensively. 



My purpose in attempting the study of the Latin American leafy Hepaticae 

 lias been threefold. The hepatics of tropical America and of the Southern Hem- 

 isphere have a special appeal to me in a number of ways. Little is known about 

 them even at the present time, but this scant knowledge has raised many prob- 

 lems of far-reaching scope. There are more endemic genera and more aberrant 

 taxa in South America than on any other continent. There are also many highly 

 evolved, specialized forms, particularly in the northern part of the area, and at 

 the same time, many simplified or primitive, radially erect forms in the south, 

 for the most part restricted to the Patagonia-Tierra del Fuego area. Some of 

 the latter genera and species have an Antarctic distribution, and are found also 

 in New Zealand, Australia, and Tasmania, some also in the South Atlantic 

 islands. Such taxa offer a wealth of new morphological fact, since in the past 

 they have largely escaped notice, having been often buried within unrelated 

 genera that are poorly represented and of little significance in the Northern 

 Hemisphere. 



The detailed knowledge of these southern taxa again raises the question of 

 origin and phylogenetic relationships of the taxa of Hepaticae as well as the 

 problems of the pathways of migration and the geographical relationships of 

 the Latin American Flora with that of other continents. 



The only possible way to attempt a study of any one of these problems was 

 to first "put the genera in order'' taxonomically, since up to now little or no 

 work has been done on the genera. It has been necessary to make a monographic 

 study (the first), of nearly every genus. 



All the literature on the Latin American Hepaticae was assembled and a 

 catalogue of all the species made. This file, together with Stephani's Species 

 Hepaticarum I -VI and his Iconcs Hepaticarum (unpublished drawings), are the 

 sources from which the list of species for each genus was compiled. 



A very large number of unnamed collections, some 10,000 or more packets-, 

 have been borrowed from individual collectors, museums, and herbaria in this 

 country, Europe, and Latin America. These have been sorted into genera and 

 slides have been made from most of them. 



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