COMPOSITE FAMILY 



COMPOSITAE 



LATE-BLOOMING THOROUGH WORT 



Eupatorium serotinum Michx. 



The Late-blooming Thoroughwort is most frequently mistaken 

 for the very poisonous White Snakeroot, page 341 ; therefore the 

 differences between them should be carefully noted. This species 



usually does not begin 

 blooming until September 

 and continues until killed by 

 frost. Sometimes it grows in 

 woods but is more often 

 found in open places and in 

 moist soil, such as river 

 bottomland, from Delaware 

 to Minnesota and south to 

 Florida and Texas. 



The stem is much 

 branched and densely cov- 

 ered with fine hairs, much 

 more so than White Snake- 

 root ever is. Also, it is taller, 

 growing 4-8 feet high. All 

 the leaves are slender pet- 

 ioled, lanceolate or ovate 

 lanceolate, sharply toothed 

 and 3-6 inches long, but on 

 the average are narrower 

 than those of the White 

 Snakeroot, being from one- 

 half inch to 2 inches wide. 

 They are 3-nerved but have 

 a tendency to be 5-nerved at the base. Furthermore, although 

 most of them are opposite, the upper ones are alternate and this 

 is never true of White Snakeroot. 



The heads are very numerous, the inflorescence being broadly 

 cymose and about one-quarter inch high. The involucre is bell 

 shaped and its narrowly oblong and hairy bracts are arranged 

 in 2 or 3 series, of very unequal length. There are 7-15 flowers in 

 each head, and they are white but not pure white as are those of 

 White Snakeroot. 



33S 



