388 MANUAL OF POISONOUS PLANTS 



Poisonous properties. Prof. Chesnut, in speaking of this plant, says that the 

 Atamasco of the southeastern United States is supposed by some persons to 

 cause the disease in horses known as "staggers." 



Fig. 168. Atamasco Lily 

 (Zephyranthes atamasco), A 

 plant of the southeastern United 

 States, supposed to cause "stag- 

 gers' in horses. 



Fig. 169. Blue Flag (Iris versicolor). The rootstock 

 is poisonous. The plant grows in low grounds. (After 

 Johnson.) 



Family IRIDACEAE. Iris Family 



Perennial herbs, frequently with bulbs, corms or tubers; leaves equitant, 

 erect, 2-ranked; perianth of 6 segments or 6-lobed, its tube adnate to the 

 ovary; stamens 3, adnate to the ovary; anthers facing outward; ovary infer- 

 ior, mostly 3-celled; style 1 or 3-cleft, stigmas 3, opposite the three stamens; 

 ovules generally numerous in each cell; embryo small; endosperm, fleshy, or 

 horny. 



About 1000 species, of wide distribution. Common native plants of the 

 family are the blue flag (7m versicolor), growing in low grounds of the North; 



