150 



THE INDIANA WEED BOOK. 



sharply toothed. Sterile or male heads in racemes 3-10 inches long, their 

 involucres saucer-shaped, 3-ribbed ; receptacles naked ; fertile heads 1-3 

 together in the axils of the upper leaves. Fruit top-shaped, 4 inch long, 

 5-7 ribbed and with 5-7 tubercles on the upper side. (Fig. 110.) 



Abundant in alluvial or moist rich soil, often forming dense 

 thickets along the borders of streams, roadsides and bottom fields. 



July-Oct. The name Ambrosia means 

 * ' food for the gods. ' ' Why it was used 

 as a generic name for the ragweed no 

 one knoweth. The man who first used 

 it may have had the equine god in 

 mind, for horses are very fond of this 

 species, often forsaking other food for 

 its juicy leaves and branches. Among 

 the poorer classes about the larger 

 towns and cities quantities of it are 

 gathered in August and September to 

 be used instead of hay. Growing, as 

 it mostly does, in lowlands, the seeds 

 are scattered far and wide by over- 

 flowing waters. It is not a very ag- 

 gressive weed and can usually be easily 

 subdued by cultivation or by mowing 

 or pulling before the flowers open. 



As one walks or drives along 



Pig. 110. Leaf, flowering branch and seed. 

 (After Dewey.) 



streams or through low ground woodlands in early autumn he 

 whiffs its peculiar odor which is exhaled readily, bounteously, to 

 all comers. To some persons it is doubtless disagreeable, but to 

 the writer it is rich, strong, powerful fit odor for the gods. The 

 plant itself is one of the largest of our annuals, often reaching, in 

 rich alluvial soil, a height of 16 or more feet in a single season. 

 Both it and the common ragweed harbor a small ash-gray, long- 

 horned beetle (Dectes spinosus Say), the larvae of which hibernate 

 in their stems. On the horse-weed the beetle is usually to be found 

 in June and July, resting in the angles between the leaves and stem. 



115. AMBROSIA ARTEMISLEFOLIA L. Ragweed. Roman Wormwood. Hog- 

 weed. (A. I. 1.) 



Erect, much branched, finely hairy, 1-5 feet high ; leaves thin, mostly 

 alternate, once or twice divided, the lobes oblong. Racemes of sterile 

 heads numerous, 1-6 inches long, the receptacle chaffy. Fruit globular, 

 armed with 4r-Q short acute teeth or spines. (Figs. 6, /; 111.) 



Probably the most common and widely distributed weed in the 



