YELLOWSTONE NATIONAL PARK 



45 



(cream) 



(red) 



Prickly Pear Cactus (Opuntia). Cactus is ex- 

 ceedingly rare in the Park ; it is found only on one or 

 two dry plateaus, and occasionally also near the Gardi- 

 ner entrance. The flattened joints, which many people 

 call leaves, are really thickened stems. This plant has 

 apparently almost lost the ability to produce leaves; 

 a few small, mouse-ear-like growths occasionally ap- 

 pear near the thorns or at the base of the flowers. The 

 flowers look somewhat like small water-lilies, with 

 many beautiful yellow or cream-colored petals. They 

 are followed by a pear-shaped red fruit, covered with 

 nests of villainous microscopic prickles and filled with 

 seeds and a juicy pulp. 



Fireweed (Epilobium). The fireweed, one of the 

 most widely distributed plants in temperate regions, is 

 exceedingly abundant in the Park, making all the road- 

 sides a blaze of color during August. The plant is two 

 or three feet high, freely branching, forming a rather 

 bushy growth. The leaves are lance-shaped, with un- 

 toothed margins, from two to about four inches in 

 length. The flowers are borne in loose spikes on the 

 upper parts of the branches. They average about an 

 inch across, have four petals, and are of a rich purple- 

 red color. 



