1921] CURRENT LITERATURE 239 
with this topic, while in the first part the status of biological paleobotany is 
outlined. How welcome a new presentation of the geologic history of plants 
must be to any paleontologist we can conclude from the fact that the only 
available books on the subject are W. P. Scuimper’s Traité de paleontologié 
végétale (1869~1874) and Sir J. Wir11aAM Dawson’s Geological history of plants 
(1888). Both books are out of date now. BERRY is probably the only living 
paleobotanist who could give us an exhaustive treatment of our present knowl- 
edge of fossil plants, including the Angiosperms, and of their geological dis- 
tribution. It is to be — that his Sketch may soon be followed by a fuller 
treatment of the same subjec 
No survey of the latest a treatises on paleobotany would be approxi- 
mately complete without paying due respect to the concluding volumes of 
SEWARD’s great reference book, which represents the most exhaustive treat- 
ment of our present information on fossil Cryptogams and Gymnosperms. 
The last two volumes deal with the Pteridosperms, Cycadofilicales, Cordaitales, 
Cycadophyta, Ginkgoales, Coniferales, and Gnetales, to use SEWARD’s own 
terminology. His book will remain for a long time the standard work on 
fossil botany and the main reference book for the students of this subject. 
The author promises in his preface to the fourth volume to publish in an inde- 
pendent volume a general review of the floras of the past, and the energy which 
allowed him to complete his monumental work after it had been started 
twenty-one years ago gives hope that he may fulfil his promise in the near 
future. The fact that neither Scorr nor SEwarRD dared to attack the intricate 
problems of the fossil Angiosperms shows clearly how much this great plant 
division is still in need of investigation. The morphological treatment of 
fossil Pteridophytes and Gymnosperms has lately absorbed the main attention 
of paleobotanists, to the great detriment of the higher orders. It is very 
much to be desired that this deficiency should soon be corrected.—A. C. Nok. 
Botany of Iceland 
The first part of the second volume of this publication, under the editor- 
ship of RosENVINGE and WaRMING, includes contributions by @sTRUPS, and 
GaLige.6 @Qsrrup has investigated the fresh-water diatom material of 
Copenhagen University, which had been assembled by 16 collectors. The 
list includes 468 species in 4o genera, 55 of the species being described as new. 
An instructive tabular survey of distribution is given under the two general 
heads of “universal distribution” and “distribution in the different parts of 
Iceland.” The table shows that 95 per cent of the Icelandic forms occur in the 
rest of Europe, and about so per cent in Asia and America. In the arctic 
4Sewarp, A. C., Fossil plants. Vols. [I‘and IV. Cambridge. 1917 and 1919. 
’QsTrup, ERNST, Fresh-water diatoms from Iceland. pp. 1-98. pls. 5. 1920. 
: rr os Otar, The lichen flora and lichen vegetation of Iceland. pp. 101-247. 
