218 BOTANICAL GAZETTE [SEPTEMBER 
The atmograph may be employed in the measurement of the transpi- 
ration of an excised branch by tying the branch into a rubber tube and 
connecting with the outlet at d’, or it may be used in other cases in which 
it is desired to measure the passage of water. 
For observation in the field the instrument must be inclosed in a 
box in order to preserve it from interference. If it is desirable to operate 
several atmometers at a single station, as described by YAPP, the atmo- 
graphs may be compactly arranged in a box with a common reservoit 
Fic. 4 
and a single chronograph (fig. 3), as many pens being used as atmo 
graphs. Experience has shown that the piping leading to the atmome 
ters should be metallic. Glass and rubber are subject to many hazards, 
not only from vandals but also from the less conspicuous members of the 
fauna. Grasshoppers sometimes exhibit a very interesting, but none 
the less disastrous, adaptation of appetite to the supply of rubber tubing. 
For a series of simultaneous records a chronograph drum rotating 
in seven days will be found desirable. The records shown in fig. 4 were 
made in the laboratory upon a chronograph rotating once in Six hours 
and with a group of four Lrvincston atmometers. The interval required 
for the evaporation of 10 cc. by the four cups has been noted to vary, 
within twelve hours, from a maximum of 113 minutes to a minimum o 
17 minutes.—W. L. ErkenBerry, The University of Chicago. 
THE SPORANGIUM OF LYCOPODIUM PITHYOIDES 
(WITH PLATE VII) ba 
So much importance has been attached at various times to the age 
shape, and development of the sporangium in Lycopodium, that any un 
forms are of interest. The rare species L. pithyoides Schlect and ae 
which is figured in a former paper,* presents certain yariations. sest 
stem tip is large and blunt, with a flattened apical region. The © oF: 
stages in the development of the sporangium agree with those of prev? 
*SToKey, A. G., The roots of Lycopodium pithyoides. Bot. GAZETTE 443573 
1907. 
ee ppt Semen Ss eck hee) 
: 
Ste Sirese 
