1S Ae ona ree oe rae 
1913] CURRENT LITERATURE * 263 
flaring gametophyte of the water ferns, with the archegonia developed outside 
the spore. Since the female gametophyte of Lepidocarpon remains entirely 
within the megaspore, that of Bothrodendron represents a more oe 
condition, in which the gametophyte is partly free from its spore.—J. M 
Id air drainage.—In investigating the physical factors influencing 
the distribution of vegetation in the Santa Catalina Mountains, SHREVE” has 
ound important differences in the temperature limits of stations at similar 
altitudes, but differently related to the ridges and valleys of the mountain 
slopes. These differences are shown to be due to valleys and cafions being 
frequently occupied by a stream of cooled air, and to amount to a difference 
in the mean minimum temperature equivalent to that usually experienced 
with an increase in altitude of 2350 feet. The influence of this cold air drainage 
seems to be most important in its effect upon the upward distribution of low- 
land species, and will do much to account for the higher range of these species 
upon the ridges and upper slopes of cafions.—G£o. D. FULLER. 
Botryopterideae.—Licnier*® has investigated Stauropteris Oldhamia, 
nd its eae UO ey 2 ee ‘ + which h £ e ne terid 
Following the theory of the meriphyte, and including the sporangial structures, 
he reaches the conclusion that Stauropteris does not belong to the Coeno- 
pterideae, which represent an advanced group, but very near to the more 
primitive Primofilices. Incidentally he presents a “genealogical tree,”’ which 
m 
have give r 
Coenopterideae (Botryopterideae) through Stauropteris as a start; (2) to the 
Marattiaceae through Archaeopteris and Botrychium, with a possible side 
branch wii to a Leptosporangiates; (3) to the Pteridosperms (Cycado- 
filicales).—J. M 
ardizing atmometers.—The difficulties involved in subjecting a 
Standar 
considerable number of atmometer cups to exactly similar conditions of 
temperature, humidity, and air movement for the period of time necessary for 
their standardization has caused LrvincsTon® to devise a table rotating once 
per minute by means of a small electric motor belted to a reducing gear. The 
cups, mounted in suitable bottles, are placed near the outer margin of the 
table, and should a very high rate of evaporation be required an electric fan is 
made to furnish a current of air crossing the table. As the efficiency of the 
atmometer is largely dependent upon the accuracy of its standardization this 
device will prove helpful to ecological workers.—Gro. D. FULLER 
7 SHREVE, Forrest, Cold air drainage. Plant World 15:110-115. 1912. 
8 LIGNIER, O., Le Stauropteris Oldhamia Binney et les Coenoptéridées la lumiére 
de la théorie du ee Bull. Soc. Bot. France 59:1-33. Jigs. II. 1912. 
9 Livincston, B. F., A rotating table for standardizing porous cup atmometers. 
Plant World cat ae 1912. 
