1918] BRIEFER ARTICLES 193 
nection with statements concerning the growth of notches of leaves 
attached to plants. It would seem, therefore, that the conclusions 
reached by Logs are not substantiated by the behavior of the plants in 
question.—E. Lucy Braun, University of Cincinnati. 
MISTLETOE VS. MISTLETOE 
(WITH ONE FIGURE) 
The specimen shown in fig. 1 was collected near Tucson about three 
years ago by Professor J. J. THORNBER of this University. Phoradendron 
flavescens, the larger plant, acting both as partial parasite and host, is 
found on species of (Quercus, 
Fraxinus, and Juglans; while P. 
californicum, the smaller one, is a 
common parasite on Parkinsonia, 
Prosopis, and Acacia. Although 
the mistletoe is of common occur- 
rence on palo verde and mesquite 
in this region, the writer has never 
before seen one species parasitic 
on another. It is interesting to 
consider water and salts, and pos- 
sibly other materials, as having to 
pass successively through the vas- ~ = 
cular systems of three different Fic. 1.—Phoradendron californicum 
plants before they reach the cells _ parasitic on P. flavescens. 
wherein they enter into metabolic 
activities. With transpiration much stronger in P. flavescens because of 
its larger transpiring surface, it would appear as if the second species 
must have a rather difficult time in securing a sustaining share of the 
ascending stream of sap. Possibly physiologists could find a higher 
osmotic pressure in the smaller species to account for its ability to 
maintain an existence in its peculiar location —J. G. Brown, University 
of Arizona. 
Sperenecon 
