468 BOTANICAL GAZETTE [DECEMBER 
although not without prudent reservations, is clear and along stimulating 
‘and evolutionary lines, with @ due emphasis of principles and the avoidance of 
meaningless facts. What is most to be commended, and unfortunately a rare 
feature in botanical textbooks, is the recognition that stable results in con- 
nection with plant evolution can be built only on the firm basis supplied by 
the record of the rocks. Perhaps the only criticism which might be made of 
the long chapter on the Conifers is that it does not include among its many and 
good illustrations some of the anatomy of the Bt a ecially as the impor- 
tance of this phase of the subject is clearly and the i inn&y recognized in the 
text. ee il tartin 
recent additions to our knowledge, enigmatical group, wu erste Present- 
ing as it does so many characters, which ally it both with '' gymnospermous 
and angiospermous seed plants, it is at once and the despair of 
the morphologist. The conclusion is reached that tue Gnetales rather eat 
sent a line of development from the same ancestry as the angiosperm 
than a primitive group from which the higher seed plants have directly a 
their origin. The authors seem to look with some degree of tolerance at teast 
on the view, which has originated in recent years from added knowledge of the 
floral structure of the Bennettitales; to the effect that the angiosperms and 
Gnetales are an offshoot of the cycadophyte stock. This view of relationship’ 
rests entirely on the enigmatical inflorescence of-the Bennettitales, and appears 
to have no support from a consideration of the structure of the gametophytes 
or the internat anatomy. While ante NnNE | the Posibinty of a legpciseaieea 
origin of the Gnetales, the authors at the sanie possible derivation 
from the Coniferales. This is perhaps a more fruittul i cuthesis, which may 
be justified when we j 1 knowledge of the past history of the group. 
e volume reviewed is a masterly treatment of our present knowledge of © 
the gymnosperms, and resumes in a particularly clear and happy way, from 
every standpoint, the evidence as to their structure, affinities, history, and 
evolution. It is vastly creditable to American morphology, and the statement 
may safely be made that there is nowhere in existence, at the present time, a 
general account of the group which is so judicial and authoritative, without ‘ 
being dull, hazy, or uninteresting. It follows of course that it is indispensable 
to every student of this important group of plants.—E. C. JEFFREY. 
Vegetation der Erde 
The ninth volume of ENGLER and Drupr’s monumental work ee vege- 
tation of the earth forms one of a series of monographic treatises that is to 
deal with the geographic features of the African floras Although he ee 
3 ENGLER, A., and Drupe, O., Die Vegetation der Erde. IX. ENGLER, < Die 
Pflanzenwelt Attias inabesandene: seiner tropischen Gebiete. Band II. pp. xi+460. 
. 16. figs. 316. Leipzig: Wilhelm Engelmann. 1908. M27 (Subscription price 
M 18). . 
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