290 BOTANICAL GAZETTE [OCTOBER 
reasons must further be added its high degree of adaptability for ger- 
minating under these less favorable serotinal conditions. 
The other form here included is Grindelia squarrosa, which occurs 
only sparsely and then almost entirely along lower slopes and fre- 
quently included in the Poa sods. On account of its scattered dis- 
tribution, the gum plant usually grows about so%™ high and branches 
much and more or less symmetrically, so that with its many heads of 
yellow ray-flowers it becomes quite noticeable in early September. 
Grindelia is a perennial from a heavy rootstock. The few awned 
achenes are inclosed in a glutinous head, consequently distribution is 
restricted, and correspondingly a gregarious tendency is to be noted. 
During the last two weeks of August several forms of secondary 
prominence in the floral tone progressively bloom. They are Solidago 
canadensis, Lacinaria scariosa, L. punctata, Artemisia gnaphaloides, 
Kuhnia glutinosa, and K. eupatorioides. Solidago canadensis, the 
most mesophytic of our goldenrods, seems to be confined exclusively 
to Poa sods in valleys and at the base of slopes. It is here gregatious 
in tendency, occurring in isolated patches or clumps. Also upee 
disturbed soil around coyote burrows it usually establishes itself in 
dense patches. It rises about a meter, with several shoots from the 
same large perennial rootstock, branches profusely, bearing so 
heads in dense panicles, and in all is most conspicuous along ee 
Grindelia at the base of slopes and in valleys. Its distribution : 
well-developed pappus is extensive, though its demands for the highes 
ecological conditions greatly restrict its establishment. 
The two button-snakeroots, Lacinaria scariosa and L. 
jough 
bloom about the beginning of the last week of August, - re 
ridges, and 
the prairies 
numerous short-peduncled heads of purplish flowers, DOT 
erect unbranched and usually solitary stem from a prom 
give these forms a most striking appearance. Copious 
assures a wide wind-distribution. 
punctala, 
* 
pappys 
