450° BOTANICAL GAZETTE [MAY 
and Olpidiaceae, ie perhaps also the Hyphochytriaceae. “He follows 
AVILLARD in believing that the Synchytriaceae show most similarity in 
cytology to the a. and were probably derived from them, but he does 
not commit himself to any opinion concerning the origin of the second group. 
—Rosert F. Griccs. 
Movement of water.—The ascent of water in vessels containing chains 
of water and air bubbles (Jamin’s chain) may take place in one of two 
ways: either the whole chain moves upward or the water alone moves while the 
air bubbles are stationary. SCHAPOSCHUIKOFF™ claims that the physical con- 
ditions of a Jamin’s chain in the conducting vessels of plants are not such that 
they prevent the movement-of the chain as a whole. Reasoning theoretically, 
he concludes that the presence of cross walls in the vessels do not hinder such 
a movement. The bubble just above the cross wall and the one just below are 
under unequal pressures, the former under reduced pressure owing to the 
suction from above, and the latter under increased pressure owing to the rise 
of water below. On account of the increased pressure the bubble below goes 
into solution, passes through the cross wall, and separates out again under the 
reduced pressure above. It is assumed that the bubbles arise only from gases 
dissolved in the water filling the vessel. They separate out when the water 
consumption by the plant is greater than the supply, causing a reduced pressure 
in the vessels. 
The author constructed a very ingenious apparatus to put the above 
theoretical conclusions to the test of experimental proof. In his apparatus gas 
bubbles began to form from the gases in solution when the pressure reached 
one-half to one-third of an atmosphere in a glass tube corresponding to a con- 
ducting vessel in the plant. As soon as a gas bubble reached the cross wall, the 
filtration of water through the membrane ceased. The manometer soon 
showed an increased pressure in the tube, due to the continued rise of water 
from below. After a short time the bubblé went into solution and passed 
through the water-saturated membrane, allowing the filtration of water to 
continue. e€ manometer now showed a sinking of pressure again. The 
passage of the bubbles by the sculpturing of the wall may be explained in a way 
similar to their passage through the cross walls. As soon as a bubble is held 
by a thickening in the wall, unequal pressures are set up, causing it to dissolve 
sufficiently to pass on.—Cuas. O. APPLEMAN. 
Chaparral.—A woodland consisting of stunted trees, seldom more than 
to feet, and apparently a response to the peculiar conditions of Southern 
California, has been studied by PLUMMER,’ and a report made upon its impor- 
44 SCHAPOSCHUIKOFF, WALK., Sollen die Luftblisschen der sogenannten Jaminschen 
Kette in den Leitungsbahnen der Pflanzen fiir immobil gehalten werden? Beih. Bot. 
Centralbl. 27: 438-444. Jigs 2. III. 
1s PLUMMER, Frep G., Chaparral. U.S. Dept. Agric., Forest Service, Bull. 85 
pp. 48. I9tt. 
