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1909] CURRENT LITERATURE 315 
three cotyledons, when the root is triarch); among cycads the cotyledonary 
bundles are not of equal value in the production of root structure, and even simi- 
larly situated bundles vary in the same species; among the cycads the cotyledonary 
bundles fuse with the plumular traces and ultimately form a central cylinder of 
variable structure. 
Root.—In Ginkgo there may be an addition of protoxylem elements after the 
root structure has been organized; in Stangeria the primary root may branch 
dichotomously; after the initial root structure has been attained, the number of 
poles may be increased at lower levels. 
The paper closes with a very useful table showing the variation in the number 
of bundles in the base of the cotyledons of the fourteen species discussed, and also 
the relation of this number to the number of poles in the root structure.—J. M. C 
Adaptation in fossil plants.—In his presidential address'* at the anniversary 
meeting (May 24) of the Linnean Society, Scorr took occasion to outline the 
evidence for adaptation from fossil plants, which naturally dealt chiefly with the 
anatomical structures of those ancient vascular plants which he has done so much 
to elucidate. No one is more competent to state the facts in reference to ancient 
plants, but the conclusions do not seem to be irresistible. In substance they are 
as follows: (1) at all known stages in the history of plants there has been a 
thoroughly efficient degree of adaptation to the conditions existing at each period; 
(2) the characters of plants always having been as highly adaptive as they are now, 
natural selection appears to afford the only key to evolution which we possess at 
present; (3) the paleontological record reveals only a relatively short section of the 
whole evolution of plants, during which there has not been any very marked 
advance in organization, except in cases where the conditions have become more 
complex, as illustrated by the floral adaptations of angiosperms; (4) the simple 
forms of the present flora are reduced rather than primitive, but such reduction 
may have set in often at a relatively early stage of evolution, and is therefore 
consistent with a considerable degree of antiquity in the reduced forms. 
These broad statements, quite apart from their application to certain views of 
adaptation, contain much wholesome truth for those who imagine that the pale- 
ontological record, as we know it, represents a continuous succession of “‘higher 
and higher” plants, for it is becoming increasingly evident that very highly 
organized plants existed at the very beginning of our record.—J. M. C. 
Morphology of Penaeaceae._STEPHENS published a preliminary account*® of 
his studies among the Penaeaceae which was noticed in this journal,*° There has 
| how appeared the full account with illustrations,2? so that the morphological 
ities 
‘8 Scort, D. H., Presidential address before Linn. Soc., 1909- pp. 15- 
‘9 STEPHENS, E. L., A preliminary note on the embryo sac of certain Penaeaceae. 
Annals of Botany 22:329. 1908. 
0 Bor. Sects 45:365- 1908. 
s, E. L., The = sac and embryo of certain Penaeaceae. Annals 
4 Siaas 2 23: ae ‘pls. 25, 26. 1909. 
