558 MANUAL OF POISONOUS PLANTS 



About 100 species of wide distribution, many native to the plains, the roots 

 of some being tuberous and farinaceous. The Indians used the tuberous roots 

 of the P. esculenta, known as Pomme Blanche, or Pomme de Prairie, of 

 the voyageurs for food. The roots of P. hypogaea and P. cuspidata were also 

 used. 



Psoralea argophylla Pursh. Silver-leaf Psoralea 



Densely silvery, pubescent with appressed hairs; stem zig-zag, divergently 

 branching, from 1-3 feet high; leaflets elliptical-lanceolate; flowers spicate, in- 

 terrupted, blue; pod oval, membranaceous, plant seldom seeding. 



' Distribution. From Wisconsin to Kansas and New Mexico to the North- 

 west territory. 



Poisonous properties. This plant was suspected of being the cause of a 

 severe case of poisoning in Story County, la., two years ago. This is the first 

 time the writer has known plants of this genus to cause poisoning, but he has 

 had some correspondence with the parties concerned and thinks there can be 

 no doubt that the poisoning was caused by the plant in question. A child was 

 seriously poisoned by eating the seeds of this plant, but she finally recovered. 

 It was thought this poisoning might have been caused by Astragalus caryocarpus 

 but the plant sent me was the above. 



13. Tephrosia Pers. Hoary Pea 



Herbs or somewhat shrubby plants; odd-pinnate compound leaves; flowers 

 in racemes or short clusters, red or white; stipules small; calyx 5-cleft; 

 petals 5; standard roundish, usually silky outside, turned back, about 

 as long as the coherent wings and keel. About 120 species, native of warm 

 and tropical regions, a few are found in the United States. 



Tephrosia virginiana Pers. Goat's Rue. Catgut 



Perennial with villous or silky and whitish hairs; stem erect and simple, 

 1-2 feet high; leaflets 17-25, linear-oblong; terminal oblanceolate, narrowed 

 to cuneate at the base ; emarginate at the apex ; flowers yellowish purple in 

 long, dense racemes. 



Distribution. In dry and sandy soil from Maine to Louisiana, west to 

 Minnesota and Eastern Iowa, to Mexico. 



Poisonous properties. This species, along with others, was formerly used 

 to poison fish. The Mexican species, T. toxicaria, gets its name from its sup- 

 posed toxic properties, and in South America, one species is commonly employed 

 by the natives to poison the fishing streams. 



The root is also poisonous to frogs and guinea pigs. 



Tephrosia toxicaria contains the glucoside tephrosin. Several active sub- 

 stances have been obtained by Hanriot * from one species, Tephrosia Vogelii. 

 Three substances were isolated; one, tephrosal C 10 H 16 O is toxic especially 

 to fish; a second toxic substance is tephrosin C 31 H 26 O 10 . 



14. Robinia L. Locust Tree 



Trees or shrubs; stipules often prickly or spiny; leaves compound, odd- 

 pinnate ; the oblong leaflets with short stipules ; flowers showy in axillary race- 

 * Compt. Rend. 1907; 498-651. Journal Chemical Society Abs. 92:386, 1907. 



