502 COMPOSITAE (COMPOSITE FAMILY) 



Means of control 



Prevent seed production by cutting the scapes while in bloom. 

 The weed grows only on clay soil and likes it moist ; drainage, lim- 

 ing, manuring, and enriching the ground enables better plants to 

 crowd it out. The horizontal rootstocks grow so near the surface 

 that cultivation turns them out, when they may be readily raked 

 away and removed. 



SWEET COLTSFOOT 

 Petasites palmatus, Gray 



Native. Perennial. Propagates by seeds and by rootstocks. 



Time of bloom : April to June. 



Seed-time: May to July. 



Range : Newfoundland to British Columbia and Alaska, southward 



to Massachusetts, New York, Michigan, and Minnesota. 

 Habitat: Recently cleared ground, wet meadows, and swamps. 



Scapes stout, appearing before the leaves, very scaly, and vary- 

 ing in height from about six inches when in first bloom to nearly 

 two feet when mature. Heads in corymbose terminal clusters, 

 each less than a half-inch broad, pale yellow or cream-color, and 

 fragrant ; they are partly dioecious, the fertile plants having heads 

 almost wholly pistillate, with one or more outer rows of ray 

 florets; the perfect but sterile flowers have tubular five-cleft 

 corollas with undivided styles. Leaves finally very large, often 

 more than a foot broad, rounded, palmately and very deeply lobed, 

 with five to seven segments also cut and toothed, glossy and deep 

 green above but densely white-woolly below especially when young. 

 Rootstocks very large and thick. 



Like Tussilago, this weed is driven out by drainage and culti- 

 vation. 



BUTTERFLY DOCK 



Petasites vulgaris, Hill 



Other English names: Butter Dock, Flea Dock, Poison Rhubarb, 



Oxwort, Pestilence Wort, Umbrella Leaves. 



Introduced. Perennial. Propagates by seeds and by rootstoeks. 

 Time of bloom: April to May. 

 Seed-time : Late May to June, 



