374 
ing thus clearly established the ranges of the forms, they have 
been allowed to exercise a certain weight in deciding in difficult 
cases of species-limitation. 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 Linnaeus have worked 
toward the natural arrangement and sequences of plant-groups. 
It is sufficient to say that only by a masterly review of morphology, 
anatomy, physiology, distribution in time and place, and even of 
such subjects as chemistry and nutritive and physiological proper- 
ties, have we been brought to an arrangement which commends 
itself to all who recognize 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 interest. 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 impor-_ 
tance that those things should be brought together which show 
the closest relationship, and the acceptance 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 
following extract from the table of contents displays the arrange- 
ment of the families :* 
PTERIDOPHYTA I 
1. OPHIOGLOSSACEAE 1 | 5. POLYPODIACEAE 8} 9. LycopPODIACEAE 39 
2, OSMUNDACEAE 4 | 6. MARSILEACEAE 33 10, SELAGINELLACEAE 44 
3. HYMENOPHYLLACEAE 6 | 7. SALVINIACEAE 34 11. ISOETACEAE 45 
4. SCHIZAEACEAE 7 | 8. EQUISETACEAE 35 | 
SPERMATOPHYTA = 49 
GYMNOSPERMAE =. 49 
* Underneath this table the authors print another, in which the common or Eng- 
lish names of the families are substituted, 
