THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN. 



VOL. IX, No. 3.] DECEMBER, 1914. [v^m^s. 



On the Anatomy of Grindelia Squarrosa. 



BY NORA E. DALBEY. 

 Plates II-YII. 



GRINDELIA SQUARROSA, popularly known as gum 

 plant, is a widely distributed representative of the or- 

 der Compositse (4, 12, 13). In many respects it is a typical 

 xerophyte. It is very hardy, with structural characteristics 

 which enable it to withstand drouth, and with a habit of form- 

 ing rosettes in the spring, which presumably helps it to with- 

 stand early frosts. With the exception of fungi, it has few 

 natural enemies (8, 9). 



A striking external characteristic is the presence of an 

 aromatic gummy exudate over the entire surface. This exu- 

 date, which is secreted by glands, is excreted in great quan- 

 tities from the flowers, while the glands on the leaf and stem 

 always excrete an amount sufficient to impart a glutinous 

 character very perceptible to the touch. 



The plant presents some unusual structural features; and 

 although it has been studied ecologically, but little anatomical 

 work has been done upon it. Beauvais (1), in 1889, published 

 an article on Grindelia robusta. His paper treats of the struc- 

 true as well as the chemistry of the plant. He calls the sub- 

 stance excreted from the epidermal glands a resin, similar to 

 that found in the resin ducts in the interior collenchymatous 

 layer. 



Glasford (7), in 1898, published his work on the chemistry 

 and histology of Grindelia robusta. He mentions resin glands 



Received for publication May 4, 1914. 



(31) 



