EUPATORIUM 



681 



above the adjoining epidermis and without subsidiary cells; the 

 non-glandular hairs are of 2 kinds: (a), uniseriate and filiform; 

 (6), uniseriate, thick-walled, pointed and more or less curved; 

 glandular hairs short, and capitate; the mid-vein is composed of 3 

 separate mestome strands, surrounded by large thin-walled water- 

 storage tissue. Resin canals are formed in the vicinity of the endo- 

 dermis in both the stem and leaves. 



FIG. 300. 1. Eupatorium perfoliatum with opposite, connate-perfoliate leaves 

 and cymose-paniculate inflorescence. 2. Eupatorium purpureum with 

 verticillate, petiolate leaves, and a large terminal panicle of flowers. 



Powder. Dark green; non-glandular hairs 2- to 8-celled, thin- 

 walled, finely striate, (a) having an acute end cell and (6) having a 

 rounded summit; glandular hairs either 6- to 8-celled in a double 

 row, and with a 2-celled glandular head, or short-stalked and with a 

 4- to 12-celled glandular head; pollen grains ellipsoidal, 0.010 to 

 0.020 mm. in diameter and with numerous centrifugal projections; 

 pappus occurring as a multicellular axis about 0.030 mm. in diameter 



