1896.] Current Literature. 243 
new species indicated in Dr. Engelmann’s manuscript notes and of 
the monographer are described, more by way of recording forms than 
with any expectation that they will stand the test of future investiga- 
tion. Artificial keys supplement the presentation of each genus which 
will serve a useful purpose in recognizing material which is generally 
incomplete. It is hoped that this bringing together of our material in 
convenient shape will provoke investigation, especially since compe- 
tent observers are multiplying in the cactus regions; and that the next 
revision will show large progress in our knowledge of this extremely 
interesting and perplexing group. 
The bacteria. 
In Engler & Prantl’s Die natitrlichen Pflanzenfamilien, the Schizo- 
mycetes or bacteria are united with the Schizophycez or fission- 
alge into the Schizophyta. The first class has recently been issued as 
Lieferung 129, and is from the pen of Prof. W. Migula, the well-known 
teriologist 
The difficulties to be surmounted in a systematic treatment of the 
bacteria are well recognized. Their simplicity of structure and vari- 
ability of function together with imperfect descriptions, the majority 
which have been recorded by non-botanical bacteriologists and the 
almost interminably confused synonymy make an exhaustive treat- 
nent of this group practically impossible f a taxonomic standpoint. 
Eee rous systems of classification have been proposed from time 
me 
ship of 
ed un 
He fu 
~ 'S and use it fora species name, as it is not only unwieldy in 
For ins 
