20 



high, with white flowers . usually striped with purple, blossoming from 

 June to September. It grows in peat bogs and swamps from Maine to 

 Minnesota, southward to Georgia and Missouri. 



LARGER YELLOW LADY'S SLIPPER. 

 Cypripedium Mrsutum Mill. 



Other names : Lady's slipper ; yellow lady's slipper ; yellow moccasin ; 

 moccasin flower; nervine; American valerian; yellows; Noah's ark; 

 yellow umbil; nerve root; Indian shoe; slipper root; Yenus's cup; 

 Venus's shoe; umble; male nervine; monkey flower. (Fig. 6.) 



Description and habitat. — A hairy or pubescent plant, 12 to 18 inches 

 high, with large, inodorous yellow flowers, appearing in May or June. 

 It grows in bogs and low woods from Maine to Minnesota, southward 

 to northern Alabama and Arkansas, and sparingly in Colorado. 



SMALLER YELLOW LADY'S SLIPPER. 

 Cypripedium parviflorum Salisb. 



Description and habitat. — A minutely hairy plant, 1 to 2 feet high, with 

 yellow and brown flowers, blossoming in May and June. It differs 

 from the preceding in the smaller size of its flower and in the posses- 

 sion of a sweet odor. It is found in bogs and low woods throughout 

 nearly the same range as the preceding species, but extends farther 

 northwestward, to the State of V\ ashington. 



Poisonous character. — The poisonous character of these plants was not 

 suspected prior to 1875, when Prof. H. H. Babcock, of Chicago, who 

 had annually been suffering, supposedly from recurrent attacks of ivy 

 (Ehus) poisoning, discovered that the affection was most probably 

 caused not by the ivy. but by the two species of lady's slipper first 

 named above. Other instances were afterwards reported, but the facts 

 were not positively ascertained until 1891, when an investigation was 

 made by Prof. D. T. MacDougal, of the University of Minnesota. It 

 was discovered that these plants are provided with glandular hairs 

 which cover the surface of the stem and leaves and contain a poisonous 

 oil. This oil is especially abundant at the fruiting season. Its action 

 on the skin is very similar to that of toxicodendrol, the active constitu- 

 ent of poison ivy (Rhus radicans), but its exact chemical nature could 

 not be ascertained on account of the small quantity obtainable. Experi- 

 ments with the stem and leaves upon individuals showed that over half 

 of them were affected by the first two species, and that the last was 

 also poisonous, but in a minor degree. No accidental cases have been 

 recorded against it. No specific antidote has been suggested. 



