WEEDS OF THE PEA FAMILY. 



91 



Seventeen species of these tick-trefoils axe known from the 

 State, two or three of which are trailing, the others erect. All have 

 purplish flowers and jointed pods, the joints varying much in 

 number, form, size and adhesiveness. (Fig. 14, I.) All are vile 

 weeds commonly known as "seed ticks,'' though no one of them 



is as common as the hoary species 

 above described. Of them Tho- 

 reau has written: "Though you 

 were running for your life they 

 would have time to catch and 

 cling to your clothes. They will 

 even cling to your hand as you go 

 by. They cling like babes to a 

 mother's breast, by instinct. I 

 have often found myself covered, 

 as it were, with an imbricated 

 coat of the brown seeds or a 

 bristling chevaux-de-frise of beg- 

 gars' ticks and had to spend a 

 quarter of an hour or more in 

 (After some convenient spot picking 

 them off; and so they get just 

 what they wanted, deposited in some other place. Growing on some 

 rough cliff side, how surely they prophesy the coming of the trav- 

 eler, brute or human, that will transport their seeds on his coat. ' '* 



Fig. 57. 



Single joint of pod shown below. 

 Britton and Brown.) 



The Spurge Family.— EUPHORBIACEtE. 



Herbs with a milky, acrid juice and small flowers, usually with- 

 out petals, the sexes of which are often bo«ne on separate plants or 

 on different parts of the same plant : leaves variable in form., size, 

 and position on the stems. Flowers, in most of our weeds, within 

 or above a cup-shaped involucre of leaf-like bracts which are often 

 colored, these involucres usually bearing naked glands. Fruit 

 mostly a 3-lobed capsule, each cell of which contains a single seed. 



A large family, mostly represented in the tropics. The castor- 

 oil plant and various species of crotons, grown for their showy 

 leaves and bracts, are cultivated examples. About 20 species grow 

 wild in Indiana, several of them forming mat plants or disks of 

 much branched vegetation similar to the carpet-weeds and purs- 

 lanes but having a milky juice. Others are erect or suberect and 

 all are separated mainly by the difference in shape and size of leaf. 



•Autumn, 38-39, 



