334 BOTANICAL GAZETTE [NOVEMBER 
TOWER (1902) discusses the bearing of these results upon the 
establishment of place-constants, and concludes “that the ‘place- 
mode’ for a species or for a character of a species should represent the 
average prevailing condition at a given place during a period of 
observation continued through years or long enough to eliminate 
the effect of secular fluctuations.’ 
It has been proved conclusively that conditions of variability 
which are a function of place are masked by others associated with 
time, and before we can satisfactorily arrive at the one the other 
must be eliminated. In the efforts which have thus far been made 
to establish place-constants this fact has not been taken into account. 
Indeed, we do not yet know how to take it into account, since no 
adequate investigation has been made of changes in variability 
which take place during the season and from season to season. It 
was to add to our knowledge of such secular variation and to col- 
tribute by its elimination to the establishment of true place-constants 
that the present study was undertaken. 
_ *In his summary Tower gives the following definition: “A ‘place-mode’ is 
the average prevailing state of a homogeneous lot of individuals [2. @., of the same 
pleomorphic condition and stage of development] characteristic of a particular ra 
and season, as determined by observations carried on long enough to cle 
effects of secular climatic fluctuations.” The limitation of a place-mode toa erner 
season was plainly unintentional, as it is inconsistent with the requirement yi tic 
observations be carried on long enough to eliminate the effects of se 
fluctuations. : 
EARSON (1902) objects to this definition as not being biometric. He says: 
mode is the least important constant involved, and in others—particul et thought, 
tion of plants—the theoretical mode is at present indeterminable. * ode, it WS not 
in studying place-modes, of limiting his studies to the theoretical : i 
unnatural so to extend the meaning of place-mode as to involve all 
relations of a population. ‘oo th 
ile it was evidently DAvENPoRT’s intention in proposing efinition will sho¥ 
mode” to use it in its strict mathematical sense, a reference to s a tion. He s4¥* 
how easy it was to make it include the entire condition of the Pe ie 
(1899a): “TI use the word ‘place-mode’ to embody a epeeirrstisan 5: 
