232 BOTANICAL GAZETTE [SEPTEMBER 
left for plankton plants; but if these plants draw their food from the soil, they 
will, through this and their subsequent decay be adding to the material in the 
water which is available for the plankton organisms. In the discussion is brought 
out the way in which the work of Kororp and of PonD may be harmonized. In 
conclusion, the author points out the logical inference that a fish pond should have 
a good soil at bottom on which plants may grow and flourish, and thus add to the 
food available for fish. The problem of the relationship of the aquatic animals 
and plants is so complicated, however, that while the author ought to point out 
these inferences, less value attaches to the economic conclusions than to the main 
thesis of the paper. The paper is valuable as being a definite contribution to 
knowledge on a question which has been hitherto in doubt, and it is the kind of 
work that is much needed in solving the problems of the plankton. In the absence 
of just such work as this, much of our plankton literature has been speculative 
in character; and while there is a real value to be attached to good guessing, in 
the long run we must have demonstrated facts as the basis of our theories.— 
C. Dwicut Marsu. . 
Miss Eastwoops has prepared a popular manual of the trees of California, 
the purpose being to give all the information necessary for identification so com- 
pactly that the book may be carried into the field. The numerous plates add 
greatly to the value of the book, many of them being reproductions of drawings 
* left by Dr. Atsert Ketiocc. Three keys are provided: the first based upon 
leaves, the second upon fruits, and the third upon the usual taxonomic char- 
acters. The trees of Oregon and Washington also are included, being placed 
in footnotes in case they do not occur in California. The only new species is 
Quercus Alvordiana.—J. M. C. 
THE RELATIONSHIP between Sigillaria and Lepidodendron has been the 
subject of much discussion, and in connection with it S. vascularis and L. selagi- 
noides have been prominent species. The identity of the two species has been 
urged and largely accepted upon evidence obtained from a study of their com- 
parative anatomy. Werss and Lomax‘ have now described a specimen consist- 
ing of a stem of S. vascularis giving off branches of L. seg iyi This demon- 
stration of actual continuity closes the discussion.—J. M 
THE TWENTY-FIRST PART of ENGLER’S Pfansenreich is a presentation of the 
sub-family Pothoideae of Araceae by ENGLER.S The sub-families of this family 
will be published in separate fascicles. Ten genera of Pothoideae are recognized, 
comprising 581 species, 489 of which belong to the great genus Anthurium, under _ 
p, ALIcE, A handbook of = trees of California. Calif. Acad. S¢- 
Occasional cen IX. pp. 86. pls. 57. 19 
* Weiss, F. E., and Lomax, ag a stem and branches of Lepidodendrom 
selaginoides. Manchester Memoirs 49: no. 17. pp. 8. figs. 4. 19° 
S$ Encier, A., Das Pflanzenreich. Heft 2r. aracie: Pua von A. Engler, 
PP- 330. Leipzig. Wilhelm Engelmann. 1905. M16.50. 
. 
