92 Error in Genera and Species. [zoE 



inevitable further variations can only find room by enlarging the 

 scope of the genus until it again comes too near its neighbors. 

 One of the trivial but annoying features of this attempt to make 

 "natural" genera is found in the care of herbaria. Most of us, 

 with some care, can put Aster into its genus covers, but which of 

 us receiving a large number of forms could put them in place at 

 once in Bucephalus, Dcellingeria, Iouactis, Leucosyris, Uucelene 

 Heleastrum Machaeranthera, Xylorrhiza, Oreastrum, Oreostem- 

 ma? etc., certainly not the author of these genera who is contin- 

 ually shifting the species. 



Genera which are thoroughly confluent would probablv be more 

 easily managed in sections than as a separate genera, as has 

 been shown by the merging of Astragalus and Phaca, especially, 

 as m a century from now the species of Phanerogams will 

 probably be less numerous in spite of the new ones yet to be 

 found. The small genera can continue to be merged, as they are 

 better known, with their nearest neighbors by the simple means 

 of omitting unnecessary detail. 



A particularly objectionable kind of genus is the one which is 

 founded largely on geographical considerations. These are only 

 too apt to be based on wanderers, and are a source of uncertainty 

 m phy togeography. These genera especially abou nd in Cruciferae. 

 The flood of "new species" in which American botanists are 

 now almost engulfed shows no signs of abating, unless it may be 

 one, that some of the most prolific show signs of discord and 

 begin to discredit each others work. One can have small hope of 

 checking the progress of botanists whose whole aim is the crea- 

 tion of as many species as possible, but. I, nevertheless, venture 

 to call their attention to a few elementary facts which some of 

 them seem to have forgotten. 



/. Although most plants are fixed to their plaee of gro7t>th, their 

 seeds may be widely dispersed. 



This would seem to be quite sufficiently obvious, yet forgetful- 

 ness of the fact has caused the re-describing of a host of plants, 

 which as years go by slowly find their proper places. The dis- 

 persion of species is often attributed to the ice age, in 



