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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 5o cm 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 gregarious 

 in tendency, occurring in isolated patches or clumps. Also upon 

 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 numerous 

 heads in dense panicles, and in all is most conspicuous along with 

 Grindelia at the base of slopes and in valleys. Its distribution by 

 well-developed pappus is extensive, though its demands for the highest 

 ecological conditions greatly restrict its establishment. 



The two button-snakeroots, Lacinaria scariosa and L. punctata, 

 bloom about the beginning of the last week of August, and though 

 sparse in their distribution, being confined to crests, ridges, and the 

 open association of upper slopes, they rise like sentinels of the prairie, 

 relieving the blaze of yellow by touches of purple. L. scariosa seems 

 more mesophytic than L. punctata, blooming usually a few days 

 later and upon upper slopes mainly. It is also much taller and the 

 heads are larger than in the latter and so more prominent. The 

 numerous short-peduncled heads of purplish flowers, borne upon the 

 erect unbranched and usually solitary stem from a prominent tuber, 

 give these forms a most striking appearance. Copious pappus 

 assures a wide wind-distribution. 



