286 PRAIRIE COMMUNITIES 



HIGH PRAIRIE ASSOCIATION 



(Stations 47, 48; Table LXVII) (Fig. 294) 



The type of vegetation which dominates the high prairie is most 

 noticeably characterized by the silphiums — the rosin-weed and the com- 

 pass plant. The former has broad undivided leaves, the latter divided 

 leaves which usually face east and west. This plant formation springs 

 up throughout the temperate American forest border area on all well- 

 drained ground. It succeeds the low prairie as the depressions occupied 

 by the latter are rilled or drained. The high prairie then succeeds the 

 low prairie just as the bulrushes succeed the pond plants; the sedges, 

 the bulrushes; and the boneset association, the sedges. All stages in 

 the development of a pond into prairie may be found near Chicago. 

 Dr. Cowles is of the opinion that shallow ponds with gently sloping 

 sides develop into prairie, while deeper ponds with steep sides develop 

 into forest. 



a) Subterranean- ground stratum. — Earthworms abound. The larvae 

 of the May-beetles and other Scarabaeidae are abundant, feeding on the 

 roots of the prairie plants. The May-beetle is often parasitized by a 

 wasp larva (Tiphia vulgaris) (Fig. 297, p. 289) (189). The eggs of the 

 2-lined locust (Melanoplus bivittatus) are deposited here in the ground. 



The 13-lined ground squirrel (Citellus ij-lineatus) (21) is a slightly 

 gregarious species, strictly diurnal, staying in during dull and cloudy 

 days. Its burrows are from 3 to 16 in. below the surface, and often have 

 five or six entrances into a larger cavity lined with grass. In a den 

 studied by Thompson-Seton the nest was centrally located. Food, 

 which includes cabbage butterflies, cutworms, grasshoppers, beetles, 

 ants, birds (shore lark and lark bunting), and vegetation, is carried in 

 the cheek pouches and stored. The species is non-social. A brood of 

 about eight young are produced in April. 



The prairie deer-mouse {Peromyscus bairdii H. and K.) (21) is still 

 probably common. According to Thompson-Seton (143) its home range 

 is about 100 yds. It is neither social nor gregarious. It is strictly 

 nocturnal and active all winter, though some seeds are stored. Its 

 food is chiefly seeds. Hawks and owls frequently prey upon it. 



Of the extinct forms several are characteristic. The coyote (Canis 

 latrans Say) was formerly common. According to Thompson-Seton 

 (143), its home range is ten miles. The den is in a bank or an abandoned 

 badger hole. The nest is a cavity 3 ft. in diameter, with an air-shaft. 

 It is not so social as the gray wolf. Three to ten young are produced 



