2 



MEMOIRS OK THE NEW YORK BOTANICAL GARDEN 



[vol. 11 



In the study of each genus the types of all species were examined, either 

 through a loan or on visits to the various herbaria. When the type, or in rare 

 cases authentic material, was not found, the species was not included; names of 

 such species are listed at the end of the genus. At least some of the illustrations 

 were made from the type. The slides made from the undetermined material of 

 the genus were then studied; they furnished valuable additional information on 

 variation and distribution, and sometimes new species. 



All the specimens that I have seen are listed in the detailed "distribution" 

 that follows the description of each species. There is also a list of the reports 

 of additional localities cited in the literature for which I have not seen speci- 

 mens; these are given by country, with author and date of publication. 



The outline of arrangement of the families and genera follows in a general 

 way that of Evans (1939), except that the family Ptilidiaceae, long recognized 

 as the repository for a large number of diverse, primarily exotic, unrelated taxa, 

 is here considered in a narrow sense (and in this sense it apparently does not 

 occur in Latin America). Some of the excluded genera do not occur in Latin 

 America, some are more closely related to families which follow later in the 

 classification, and some have been the bases for new families. 



The sequence of the families and genera is not meant to be phylogenetic, for 

 our knowledge is as yet too meagre to attempt to align these geologically very 

 old, widely divergent, morphologic-taxonomic units in such a way. However, the 

 first part contains most of the families with primitive characteristics and many 

 genera, some very large, that seem to be geologically very old, as indicated by 

 the several diverse lines of specialization coupled with diverse patterns of dis- 

 tribution within them. 



The citation of the place of deposit of the type specimen has been exceedingly 

 difficult, particularly for the older species. Many of the earlier hepaticologists 

 sent a portion of the original collection of their new species to their coworkers 

 and other herbaria. All these packets are labeled "original" or "type," either 

 by the original author or later by someone else. Through the buying and selling 

 of collections, and through the confusion and destruction of the war years, or 

 often just through neglect over the years, it is often impossible to be sure which 

 one of the several "types" is the specimen actually used by the author. Who 

 is there to say which is the type and which the isotype following the Rules? 



I feel that it is correct to designate all of these portions of the original col- 

 lection (often only four or five stems in all), as the type, citing the several her- 

 baria in which they are to be found. However, in an attempt to follow the Rules, 

 I have arbitrarily cited one part as the type, the rest as isotypes, and have no 

 doubt made many errors in so doing. For the species described by Stephani, the 

 specimen at Geneva (if so indicated) is always designated type, and the parts 

 of the original collections from Stephani's herbarium now at the Farlow Her- 

 barium the isotype. When no type specimen has been found at Geneva it is 

 assumed (perhaps incorrectly again) that all the material was returned to the 

 collector or to the herbarium that had sent it out for naming, and the type is 

 cited as being there. 



ACKNOWLEDGMENTS 



The Manual would not have been possible without the financial assistance of the National 

 Science Foundation which has been generous in its support, with two successive grants, G 2616 

 and G 7147. These have made possible the purchase of scarce books and photostats to com- 

 plete my literature of the Latin American Hepaticae, the study of type species in European 

 herbaria, and a trip through Latin America. In addition, they have provided assistance with 



