1896, ] Briefer Artities. 169 
“gives rise to an extra-axillary branch” is the true axillary bud, as the 
upper bud plainly is in Amorpha fruticosa, Cercis Canadensis, and 
the above mentioned Juglandaceze.—Gro. H. SHULL, Sulphur Grove, 
Ohio. 
EXPLANATION OF Pate VI.—F ig. 1. Axillary bud of Spirea sanguisorba L., 
the accessory buds just making their appearance.—Fig. 2. S. : 
buds fully developed as seen in the winter.—Fig. 3. A node of Diervilla trifida 
Moench.—Fig. 4. The same. One of the axillary buds has been destroyed and 
Fi 
densis —Fig. 6. A node of Amorpha fruticosa L.—Fig. 7. Node and thorn of 
Gleditschia triacanthus L.—Fig. 8. A node of /uglans nigra L._Fig. 9. A node 
of Ampelopsi's quinguefolia Mx.—Fig. 10. A section of the bud of same. —Fig. 
- The first two nodes and the recurring series of three nodes of Ampelopsis 
guinguefolia, 
Relations of eutinized membranes to gases,—During the course of 
some experiments on the relations of plant membranes to gases, I had 
occasion to make an estimation of the rate of diffusion of CO, through 
* gtape skin, and obtained a somewhat unusual result. In this ex- 
Periment a cleaned skin of a Concord grape was fitted, by means of 
*a!lng-wax, to one end of an open glass tube 30™ in length and 5™ 
‘nternal diameter, filled with boiled water, inverted in a dish of mer- 
cury, and the water displaced by washed carbon dioxide (MacDougal, 
Exp. Plant Physiology 36, 37. 1895). By the exosmose of the gas the 
mercury column was slowly drawn upward into the tube, for seven 
Stationary for eleven days and then slowly began to fall until ten days 
later it became Stationary 1™ below the membrane. It retained its 
height with barometric and thermometric variations, from Nov. 1, 
"894, to Dec. Io, 1895, when the apparatus was accidently shaken so 
roughly that the vibration of the mercury column ruptured the mem- 
‘ane and the column fell in a few minutes. An examination of the 
ce of tape skins to filtration under pressure of 44.5™ of mer- 
"NY for nine days (Proc. A. A. A. S. 48: 277. 1895) and Wiesner 
