IHE ALUMNI JOURNAL. 



247 



highest quality, and a remarkable degree 

 of naturalness has in most cases been at- 

 tained. In many cases, as, for instance, 

 in that of Xyris torta, the figures are ex- 

 ceedingly beautiful. Drawn usually from 

 dried specimens, the figures have after- 

 ward been compared as often as possible 

 with the living plants To have drawn 

 all the figures from life, would, doubtless, 

 have still further improved the appear- 

 ances, but this was absolutely impossible. 

 Natural considerations, which have 

 been allowed to control the entire plan- 

 ning of the work, are manifest in the 

 selection of the boundaries selected for 

 the flora. Even the announced limits 

 are over-stepped when necessary to com- 

 plete a natural region, as in the inclusion 

 of the extra-limital portions of Nebraska. 

 That the relations between geography 

 and botany have been attentively studied 

 is evidenced in more than one way. Both 

 ocal catalogues and local herbaria have 

 ibeen thoroughly searched to determine 

 the precise range-limits, and great care 

 has been exercised in indicating clearly 

 the habitats of the species. In no pre- 

 ceding work has the subject of range 

 been so well elaborated. We find in this 

 work, moreover, about the first systematic 

 attempt to give the altitudinal distribu- 

 tion. So little attention has been paid 

 by collectors to this important subject 

 that the information here accumulated by 

 Dr. Britton can hardly be regarded as 

 more than a working basis, but as such 

 its value will prove very great. Not the 

 least valuable of the geographical features 

 is the statement, in a general way, of the 

 extra-territorial ranges of the species. 

 Having thus clearly established the 

 ranges of the forms, they have been al- 

 lowed to exercise a certain weight in 

 deciding in difficult cases of species-limi- 

 tation. So important has this subject of 

 plant-geography come to be regarded in 

 modern botany that we may indulge a 



little natural pride in the appearance of 

 so thorough a study of it by American 

 authors. 



It is scarcely necessary to review here 

 the slow and laborious process by which 

 systematic botanists since L,innaeus have 

 worked toward the natural arrangement 

 and sequences of plant-groups. It is suf- 

 ficient to say that only by a masterly re- 

 view of morphology, anatomy, physi- 

 ology, distribution in time and place, and 

 even of such subjects as chemistry and 

 nutritive and physiological properties, 

 have we been brought to an arrangement 

 which commends itself to all who recog- 

 nize and value a deciding influence higher 

 than the dictum. Such inconvenience 

 as results from working under the new 

 arrangement may fairly be regarded as 

 due to a failure to have taken natural 

 relations into consideration. To those 

 who have done so, the new arrangement 

 will present no other unfamiliarity than 

 that of a new thing which has been long 

 and eagerly sought. As to beginning at 

 the upper or lower end of the sequence, 

 the reviewer confesses to but faint inter- 

 est. It would appear to matter but little 

 whether we turn to the right or to the 

 left as we enter the herbarium. But it is 

 of vital importance that those things 

 should be brought together which show 

 the closest relationship, and the accep- 

 tance or non-acceptance of any portion of 

 the new arrangement may best be decided 

 upon the basis of those principles upon 

 which it has been founded. The follow- 

 ing extract from the table of contents 

 displays the arrangement of the families ;* 



PXERIDOPHYTA I 



1 Ophioglossaceae i 6 Marsileaceae 33 



2 Osmundaceae 4 7 Salviniaceae 34 



3 Hymenophyllaceae6 8 Equisetaceae 35 



4 Schizaeaceae 7 9 Lycopodiaceae 39 



5 Polypodiaceae 8 10 Selaginellaceae 44 



II Isoetaceae 45 



♦Underneath this table the author prints another, in 

 which the common or English names of the orders are 

 substituted. 



