348 hackel's andropogone^. 



it to a var. has put us to this extra toil in order that his " species" 

 may be of nearly equal value (a hopeless aim). 



The most novel and the most questionable feature in Hackel's 

 volume is in the handling of the subordinate divisions of genera — 

 the subgenera, sections, subsections, &c. Alph. DeCandolle has 

 laid down that, in a genus, let us say, of sixteen species not divided 

 into subgenera or sections, all the characters that apply to the 

 whole sixteen species shall be placed in the description of the 

 genus, and none of these characters shall be repeated in the diag- 

 noses of the species, which latter ought to be strictly diagnostic, 

 I. e., separating the species from each other. This plan avoids 

 repetition and looks fair, and Hackel carries it out logically down 

 through all his subdivisions of genera — down to subsubsections 

 and lower. In the lowest group, the diagnosis of a species thus 

 will contain only the trivial characters which distinguish it from 

 the closely-allied few (in Hackel usually 1-5) species in the group ; 

 the essential characters of the species will be scattered through the 

 headings of the subsections, sections, subgenera. These headings 

 also, on the Candollean principle (ridden to death), include as much 

 as possibly can be averred of all the species beneath them, i. e., they 

 are as full as possible ; for example, one on p. 232 contains 196 

 words ; they frequently contain more than 100 words. If it is 

 wished to check a specimen of Isclmmum latifolium Kunth by the 

 book, on turning to p. 236 we find no diagnosis, because the species 

 is the only one in the subsection ; to get its diagnosis we add the 

 characters oiHio those of ** (p. 234), to those of /3 (p. 232), to 

 those of b (p. 211), to those of A (p. 202). It is true that, by this 

 arrangement, repetition has been avoided, and the principle of 

 DeCandolle pushed to its logical limits. To use the book, even in 

 a genus like Ischamum, it is necessary first to draw up on a sheet 

 the characters of all the sections, subsections, &c., so that it may 

 be seen what the different headings are contrasted against. The 

 genus Andropofjon on this system is so appalling that it may be 

 fairly doubted whether many botanists, before the next monographer 

 of Andropogonece, will sufficiently master it to work with it in naming 

 plants. The author has in this single case so far condescended as 

 to give a "Conspectus Subgenerum " at the head of the genus; 

 otherwise he has left each botanist to make his own tabular views 

 of the sections, &c. Few experienced herbarium-workers can make 

 much use of Planchon's AmpelidecE on taking it up to name thereout 

 a few Vines ; it requires to study it a fortnight or so before you can 

 work w^th it. Hackel's volume is certainly easier to work with 

 than Planchon's ; still it is to be feared the volume will be of little 

 use to botanists, except those few who can give up several days to 

 one tribe of Grasses. But for what object has this fearful dis- 

 location of the essential chariicters of species been submitted to ? 

 Merely to avoid repetition ! These characters might, in the manner 

 of Kunth, be placed in tlie diagnosis of each species in four to six 

 lines of print, without a letter of the book being otherwise altered ; 

 the book would have been lengthened at most by thirty pages ; 

 or the diffuse "descriptions" might have been made three or four 

 lines shorter each, in which cnse the book would not have been 



