38 GRIGGS: OBSERVATIONS ON THE BEHAVIOR 
But allowing for all the changes which might be made in the 
classification by one of wider field experience than the writer, it’ 
seems certain that failure of the reproductive functions is an un- 
important factor in the termination of ranges in this region. Most 
plants normally produce such an enormous quantity of surplus 
seed that even a considerable falling off in seed production would 
not necessarily affect the abundance of the species. 
The success of the seedlings is apparently much more important 
than the number of seeds. Rubus odoratus is a case in point. Al- 
though flowers are produced in abundance the fruit does not set 
well so that it is usually difficult to find a berry perfect enough to 
be palatable. In the aboriginal forest this species led a precarious 
existence on the cliffs and other places unoccupied by trees, where 
sufficient light and moisture were obtainable. But with the de- 
struction of the forest it is becoming one of the commonest plants 
of the ravines. It is clear therefore that its failure to fruit well 
is not a controlling factor in fixing its range. 
Vegetative propagation plays of course a role of considerable im- 
portance in this connection. The most striking instances are Phlox 
stolonifera, inte eau ter and the lycopods which would 
hardly maintain tl ves were it not for their stol d gemmae. 
On the other hand it seems safe to assign failure of the repro- 
ductive mechanism as the limiting factor in the case of those species 
which do not fruit well and at the same time are uncommon, being 
without means of vegetative multiplication. These include only 
Asclepias Sullivantu, Aseculus octandra, Asclepias variegata, Ble- 
phariglottis lacera, Napaea dioica, Passiflora lutea, Quercus minor 
(?), Stylosanthes biflora and the lycopods, L. obscurum and L. 
clavatum, which although forming large masses by their runners 
are yet scarce, especially the latter, of which only a single bed has 
been discovered. 
The next question to arise is as to what differences in abundance 
there may be between the different geographical groups represented 
in the lists. What differences are there between northern and 
southern or eastern and western plants? A comparison of the 
lists given above with those presented in the bese pei paper* 
gives the data shown in tabular form belew. 
" * Griggs, Robert F. Observations on the geographical pene of the Sugar 
Grove flora. Bull. Torrey Club 40: 487-499. f. I-10. 10S 19 
