88 BOTANICAL GAZETTE [JANUARY 
same season SHERFF also obtained data upon the evaporation rates in different 
strata of the marsh vegetation, showing the evaporating power of the air to be 
300 per cent greater in the top stratum of the Phragmites association than in the 
lowest, while the difference became three times as great in the Typha associa- 
tion. These results confirm those of Yapp” for a sedge vegetation and those o 
the reviewer for the beech-maple forests, warranting the conclusion that plants - 
may grow in proximity with each other and yet, vegetating in different horizon- 
tal strata, be subject to widely different growth conditions.—Gro. D. FULLER. 
History and origin of monocotyledons.—Horwoopb” has done useful service 
in bringing together, in convenient form, the evidence of fossil monocotyledons. 
The record of each family is recited, and the summary shows that the first 
authentic specimens are from the Cretaceous, and that in the Tertiary or Post- 
Tertiary 24 families out of about 30 are represented. In dealing with the origin 
of monocotyledons, Horwoop gives a synopsis of most of the views that 
have been advanced and reacees = following general conclusion: that the 
monocotyledons and dicot ivergent series from a common ancestor; 
that among the dicotyledons there has been “‘progression and differentiation,” 
while among the monocotyledons there has been “‘retrogression and even some 
reduction from a common ancestor of the primitive angiospermic type.” This 
primitive type, by the way, ‘“‘resembled an alismaceous or liliaceous type, on 
the one hand, and a ranalian type on the other,” and in the background of this 
primitive stock the author sees the Cycadafilicales and Bennettitales. The 
mass of facts brought together will be very uSeful, even if the conclusions are 
not convincing.—J. M. C. 
Fourth International Botanical Congress.—The first circular of the Inter- 
national Botanical Congress of 1915 has been issued. The sessions will be held 
in London from May 22 to May 29. Membership is secured by subscribing 
to the regulations of the congress and by the payment of a subscription of 
15 shillings. Ladies accompanying members may attend the meetings and 
excursions of the congress on payment of 10 shillings each. The presidents of 
the organizing committee are Professor F. O. Bower, Sir Davip PRAIN, an 
Professor A. C. SewaRD. The general secretary is Dr. A. B. RENDLE, British 
Museum, Cromwell Road, London, $.W., to whom applications may be made. 
R. H., On stratification in-the vegetation of a marsh, and its relations to 
evaporation and temperature. Ann. Botany 23:275-320. 1909. 
#8 Bor. GAZ. §54:424-426. 1912. 
2 Horwoop, A. R., The past history of monocotyledons, with remarks on their 
origin. Scottish Bot. Review 1:164-180, 216-234. pls. 1-4. 1912. 
