52 FLORA OF WASHINGTON AND VICINITY. 



On the other hand, the British authorities are followed in uniting the 

 Saururacem with the Piperacece, and also in placing the Paronychiece, 

 reduced to a sub-order, under the lUecehracecc ; but from the certain 

 relationship of this order with the CaryophyUacew, it is deemed unnatu- 

 ral to separate these two orders by putting the former into the Monochla- 

 mydeous Division. (See American Naturalist^ >;ovember, 1878, p. 726.) 

 On the same ground of apparently close relationship, I have followed 

 Bentham and Hooker in abolishing the Callitrichacew and placing Calli- 

 triche in the Haloragew. But I have followed Gray and Watson in 

 keeping the Fumariacece distinct from the Papaveracece, and the Lobe- 

 liacew from the Canipanulacew^ as also in preserving the Ericaceae intact, 

 and not slicing off the Vacciniacew from one end and the Monotropece 

 vfrom the other, as is done in the Genera Plantarum. 



In the Gamopetalm before, and including Gompositce, in the Monochla- 

 mydece, and throughout the Monocotyledons, serious difiSculties occur in 

 consequence of a want of recent systematic works from the American 

 point of view. In nearly all cases the names as well as the arrangement 

 of Gray's Manual, fifth edition, have here been adopted. I have, how- 

 ever, been able to avail myself of a number of recent revisions of genera 

 made by Gray, Watson, and Engelmann,* and published in various 

 forms, chiefly in the Proceedings of the American Academy of Arts and 

 Sciences. I have also derived many useful hints from the Flora of Cali- 

 fornia, from the botanical reports of the various Western surveys, from 

 Sargent's Catalogue of the Forest Trees of Worth America, and from the 

 Flora of Essex County, Massachusetts. 



Mr. M. S. Bebb, of Eockford, 111., has shown great kindness, not only 

 in determining all the uncertain Salices, but in generously drawing up a 

 ilist of them in the order of their nearest natural relationships, which is 

 ifollowed implicitly in the catalogue. 



For the ferns, the magnificent work of Professor Eaton has furnished 

 ^everything that could be desired, and is unswervingly adhered to. 



The following genera in the Compositce have been changed by Bentham 

 and Hooker, but the new names cannot be adopted until the species have 



* Wliile I have gladly adopted the arrangement of the species of Qiiercus, decided 

 upon by Dr. Engelmann after so careful a study, I cannot do so without recording a 

 gentle protest against the position to which he assigns Q. palustris, viz., between 

 Q. falcata and Q. nigra, and far removed from Q. rubra. Not only its shallow, finely- 

 scaled cup, but especially its light-colored buds and thin early leaves, as also a special 

 fades belonging to its amentsand foliage, ally this species with Q. rubra, and distin- 

 guish these two species as a group from all others found in this flora. 



