354 BOTANICAL GAZETTE [NOVEMBER 
In discussing the general problem of the phylogeny of gymnosperms, 
the author fairly states the contending claims for its polyphyletic and mono- 
phyletic origin, but plainly inclines to the latter position, He sees no reason 
for imagining any connection whatsoever with the Lycopodiales, and still 
less with the Equisetales. The connection of Cycadales and Bennettitales 
with Filicales being considered as established, both through morphology and 
the paleobotanical evidence of such a group as Cycadofilices, “the derivation 
of the other gymnosperms centers about the extinct group Cordaitales,” 
whose affinities with the Cycadales are clear.—J. M. C 
Tropical Nature. 
COSTANTIN, the well-known French botanical philosopher, has issued a 
second volume in the series known as Bibliothéque Scientifique Internation- 
ale. His studies in various lines of botanical research, and especially his 
classic ecological papers on aquatic plants, have well fitted Costantin, both for 
his work on Adaptation-Evolution? and for the work which is the subject of 
this review.3 In the introductory chapters the author gives a realistic picture : 
of the virgin forest of the tropics, and vividly recounts the first sensations that 
one has in these new scenes. After a few remarks on tropical climates, 
Costantin plunges at once into the very deepest ecological problems of the 
tropics. He first discusses the origin of forests, and takes up some of the 
types of trees that are peculiar to tropical forests. An interesting chapter on 
leaves follows, and some of the most recent studies, as those on hydatl cs 
are introduced. After a few pages on flowers and fruits, the author give ad 
brief survey of the geological history of forests, holding to the older view 
that the present tropical forests are fragmentary, but yet lineal descendants 
of those which have passed away. . The lianas come in for an excellent treat- 
ment, four chapters being devoted to a discussion of the various classes cy 
their origin, Chapters follow on epiphytes, especially those found per sh 
tree tops; parasites of various classes; symbiosis, one chapter dealing wit) 
saprophytes, the other with the réle of ants and other animals in influenci"g = 
plant life. Saprophytism at one time would not have been given anon 
of symbiosis, but recent studies on mycorrhiza makes such ace haptet 
necessary. The strictly botanical part of the volume closes with ¥ pie 
ic 
on mangroves and one on island floras, the latter from the geogtP 
point. ‘nal 
a cally 0 
Though the volume is entitled Tropical Nature, it is confined p << 
the plant world of the tropics, The last chapter is a curious excep 
p., with 177 
? Les végétaux et les milieux cosmiques (Adaptation-Evolution). 292 PR o 
figures in the text. Paris. 1808. ie 
>38 CosTANTIN, J.: La nature tropicale, 8vo. pp. 315- figs. 700. tee 
Alcan, 1899. 6 fr, pe 
