GRASSES OF IOWA. 



395 



HYDROPHYTIC. 



These grasses are unable to withstand the injurious influences of dry 

 soil and weather. Bulliform cells are rather poorly developed. The grasses 

 grow in water or in moist places, however, some species grade into meso- 

 phytic, as Panicum Crus-galli } an extremely variable species. We may note 

 here that where these grasses occur, the soil is much colder, and the sea- 



Fio. 267. Andropoyon scoparius and A. provincialis with Solidago 

 rigida. Ames, Iowa. (Charlotte M. King, Photo.) 



son is later than where the soil is well drained. The typical hydrophytes 

 are represented by Zizania aqunhca, which occurs not only in the bogs of 

 northern Iowa ( these very closely resemble the genuine peat bogs of 

 mountains) and those occurring in Wisconsin and Minnesota but also 

 occurs in the bayous of rivers and along the small stream;. In eastern, cen- 

 tral and western Iowa. Panicularia aquaiica, P. fluitanSj common in 

 most bogs of central and northern Iowa, and the Scolochloa festucacea, 



