528 BOTANICAL GAZETTE [JUNE 
The figures of 60 per cent bare ground for May 30 in table I should 
not be understood to mean that the other 40 per cent is fresh growth. 
Indeed, there is almost nothing green at that time of year. The 
vegetation cover is made up of the dry grasses, sedges, and flowering 
herbs of the previous summer. By July 1, however, the new growth 
has reached its maximum. This rapid development is necessitated by 
the shortness of the growing season. Only such plants as can mature 
quickly are able to exist under the rigorous climatic conditions. 
TABLE II 
PERCENTAGE OF BARE GROUND IN MEADOW GRASSLAND 
May 30, June 12, June 28, July 12, July 26, Sept. 1, 
Quadrat Igt2 1913 IQI3 1913 1913 Igi2 
Rite Se 45 20 ° ° ee be) 
Me oe ea 5 Pe bent Cotes ase 20 10 Io 10 
Average. 22 56). ae 20 10 5 5 ike) 
In the dry grassland, as will be seen from table I, there is a consider- 
able proportion of bare ground, even at the height of the season in early 
July. The meadow association, on the other hand, shows little or no 
vacant space at that time. The differences depend chiefly on the tex- 
ture of the soil, the finer grained material of the meadow holding more 
moisture and permitting more luxuriant growth. 
It is interesting to note that when introduced weeds get a foothold in 
the region they do not become established in the open association of dry 
grassland, but in the already closely grown meadow.—F RANCIS RAMALEY, 
University of Colorado, Boulder, Colo. 
THE OXIDASES OF ACID TISSUES 
According to recent theories, the oxidases play an essential part in 
respiration. If these theories are correct, it follows that oxidases must 
be present in all organisms. But a serious difficulty is encountered in the 
fact that many plants have been reported to be free from oxidases. If 
this is really the case, it would seem that these theories must be aban- 
doned, or at least greatly modified. 
It appeared to the writer that in view of the importance of the subject 
a fresh investigation was needed. From the results of the writer’s 
experiments it is evident that in many cases the reported absence of 
oxidases is to be ascribed to faulty methods of investigation. The 
