COLONY-CHARACTERS 2d 
Most of the Macrophylli and Curvescentes form conspicuous colonies 
with large leaves which remain throughout the season. Colonies of 
the Divaricati have capricious or merely vernal developments of 
radicals. The character of the colony depends much on the 
length of the rootstock, which varies with the species somewhat, 
and also within the species according to soil and position in rock- 
cleft or swampy ground. A. guescens may cover the ground with 
a dense colony for 200 feet; A. curvescens, A. Schreberi, A. um- 
belliformis, A. multiformis, produce strong colonies; but it is re- 
served for A. macrophyllus to cover the ground loosely with radi- 
cals for many rods together, or even for the half-mile, as among 
second-growth sprout-lands of the Cattaraugus Indian reservation. 
Dense colonies. — A. sociabilis and A. ulmarius are remarkable 
for their compact bunch-like colonies or stools formed by very 
short rootstocks of one or one and a half inch in length. 
Tsolation. —I have never found A. viridis growing as a colony, 
which is remarkable considering the resemblance of its leaves to A. 
macrophyllus ; this isolation of individual growth is one reason for 
considering A. viridis to bea hybrid. Similar though not such abso- 
lute isolation on the part of A. divaricatus fontinalis suggests a 
possible hybrid origin for that form also. Isolation of the indi- 
vidual on the part of A. macrophyllus sejunctus does not call for 
the same interpretation, however, because it is unaccompanied by 
any other character suggesting hybrid origin; the characteristics 
of sejunctus are such as are presumably assumed by certain seed- 
lings derived from A. macrophyllus which have happened to start 
apart in grassy sward and which would, perhaps, in course of 
years, become assimilated in their descendants to the normal A. 
macrophyllus ; hence my classification of sejunctus as but a sub- 
species. 
= Characteristic length or shortness of rootstock seems to hold 
fairly constant throughout most species, as in A. multiformis, A. 
macrophyllus, A. divaricatus, where they are long and horizontal, 
A. roscidus and A. carmesinus, where they are much inclined to 
upturned or even vertical growth on account of preferred habitat 
among rock-clefts, A. sociabilis and A. ulmarius where they are 
very short but subhorizontal, A. undulatus, A. cordifolius and 
relatives, where they are ascending points from the crown of the 
