OF SOME SPECIES AT THE EDGES OF THEIR RANGES 39 
a ale ela 2s | 3 §13 || | ac >|, | 3! F| : 
[S/S 2188 0 JAS elo lSglelinmy Sie. Piaegies) & | 
ElESESTSCEE Eels Se ez gules] & Ssoy 2/3 
\Elen|s” oe BSL iM ip sisiiog HE Ssleel ~ Bsn! os 
SiSzaz3 0/7) Pee es SCeRe| 2 sss) 3 | 
gee P| | Peer) easy EPS PE! S| 
Alleghenian..... 18/0 | 1 | 4|65]4/4/ 22 7\l5 | 5 | 281 6 5 1531 9 |30 
New England | im 
Appalachian../11; tT | 0 | 0|80]0/0| 0/2, 0/0) o] 1) 6) 6 93| I |14 
Appalachian....| 7) 4} 0 | 0/92]0/0| o|r)) t/|/o0}| 8] 1] 4/3 66 | 3 \12 
Carolinian...;..|16| 2 | 0 5 |68)2/3|15|4| 2 | 4 | 18] 6 |rr| 3 | 61] 6 |32 
stern . 555% 3) 1:| 2 | 0 | 40]3/4] 47/3) 0 ri ats 2/| 2 60| 5 15 
Northern 035. SP toe 4 el oe oat) 0,0) 0} 3 2\ 1 66/3 |9 
1 t ' 
This table does not indicate that in this region species behave 
differently on different edges of their ranges. Except in one case 
the differences shown are too small to be significant in view of the 
small numbers involved. The abundance and reproduction of 
species terminating in this area are evidently matters concerned 
with the individual peculiarities of the particular species rather 
than with its geographical position. The large number of rare 
plants among those from the west is, however, very striking. 
When this is coupled with the fact that a large proportion of them 
are known from scattered stations far to the eastward of their 
main range, it becomes significant. 
There is a widely held idea, which owes its origin I believe to 
Blytt* though it may be much older, that, whereas a species may 
be ubiquitous in the center of its range, occurring in all sorts of 
habitats because highly favored by climate, at its areal limits it 
will be closely limited to those conditions which are most favorable 
to it. According to this reasoning we should be best able to 
determine the conditions most favorable to any given species by 
observing its behavior on the edges of its range. The theory is so 
plausible that one would like to accept it and apply it to our 
plants. But unfortunately certain of our Sugar Grove plants do 
not seem to behave according to expectations and raise doubts 
concerning its validity. 
The chestnut is one of the most typical of all the ‘‘calcifuge”’ 
plants and its distribution in central Ohio fulfils expectations in 
this regard. It is absent from the limestone country about Colum- 
bus but appears immediately as one enters the outcrops of sand- 
*I am unable to find the reference to Blytt’s paper; see also Cowles, Physio- 
Sfaphic Ecology of Chicago and Vicinity. Bot. Gaz. 31: 83. 1901. 
