MISSOURI PRICKLYPEAR 



Opuntia polyacantha Haworth 



The Missouri pricklypear is one of the commonest of the cactuses. 

 The flowers are so beautiful that one forgets the wicked spines and the 

 still more dangerous spicules, which are found on the thick stems or 

 flat joints, until one endeavors to gather them. In the bright sunshine 

 of early morning the dry prairies in some sections are dotted with masses 

 of pale sulphur-yellow flowers, turning salmon in the late afternoon as 

 they fade. The sensitive stamens are sometimes yellow and sometimes 

 red, while the stigma-lobes, in the center, are always green. The irritable 

 stamens are one of the provisions which nature makes to bring about 

 cross-pollination. Bees visit the cactus flowers to obtain the nectar. 

 When one of them settles upon the stamens, which spread widely apart 

 in bright sunlight, these at once turn inward and downward, covering 

 the insect and depositing the pollen on its back, legs, and head. This 

 pollen is then carried by the insect to the next flower and dropped upon 

 its stigma-lobes. Below the bright-colored petals is the spiny ovary, 

 which ripens into a dry, many-seeded fruit, this pricklypear being 

 one of the few which are not juicy. 



The Missouri pricklypear may be found in dry places from New 

 Mexico, Missouri, and Wisconsin to Alberta and British Columbia. 



The specimen sketched was obtained near Medicine Hat, Alberta, 

 Canada, at an altitude of 3,500 feet, a locality near the northern range 

 of this species and also near the northern limit of the Cactus Family. 



PLATE 3 5 



