Introductory. 
13 
(It is worth nothing that a considerable number of new species are about to 
be published in the Bulletin of the Torrey Botanical Club and in the Botan¬ 
ical Gazette.) Two genera, Eucladium and Merceya, 1 have been indicated 
as new to North America. The former has been included in the key to 
genera. The relationship of the latter is so problematical that I have been 
compelled to omit it. 
The number in bold-face type following the name of a genus in the key to 
genera refers to the page of this publication where the key to its species 
may be found. The other number, in ordinary type, is that of the page in 
the Manual where it is described. When there is only the latter the genus 
contains but one species. The number following the species (in the keys to 
species) is the same as it bears in the Manual. 
It will be found in a number of cases that the keys contradict characters 
assigned in the Manual. I have not knowingly permitted such contradiction 
without having good reasons therefor, so that they must be considered as 
corrections, and not accidental. There may be mistakes among them; it is 
highly probable that there are some elsewhere. I should be glad to receive 
notice of errors or omissions from any who detect them. 
My thanks are due to Mrs. Elizabeth Gr. Britton, for kind assistance in 
several points. 
Charles R. Barnes. 
University of Wisconsin, February 8, 1890. 
1 Merceya latifolia Kindberg: Bull. Torr. Bot. Club xvi (1889) 94. 
