PUBLIC PARKS OF IOWA 171 



FLORA OF THE BOGS OF CERRO GORDO AND WORTH COUNTIES. 



By L. H. Pammel. 



These bogs are interesting from a phytogeographical standpoint. We 

 have here representatives of a flora common in Minnesota to the north 

 and the bogs of western Wisconsin. Many species have, however, dis- 

 appeared in their immigration southward and northward. The conditions 

 favorable for the development of these glacial plants have gradually 

 disappeared, owing to the absence of proper soil and temperature condi- 

 tions. The long and hot summers greatly increased the heat of the soil 

 and water in which these plants thrive, hence their extermination. A 

 few illustrations will 'suffice. The Cirsium muticum, though common in 

 these bogs, occurs more commonly in Wisconsin marshes that are fairly 

 dry during the latter part of the season. The same may be said of par- 

 nassus, (Parniassia caroliniana), dragon's head (Chelone glabra), mead- 

 dow rue (Thalictrum purpurascens) and Lousewort (Pedicularis lanceo- 

 lata). The Bog willow (Salix Candida), kaln'es lobelia (Lobelia kalmii) and 

 cowbane (Cicuta bulbifera) are equally common in the bogs of western 

 Wisconsin and Worth county. The beaked willow (Salix richardsonii) and 

 pussy willow (S. discolor) are found throughout the Wisconsin drift area. 

 The holy grass (Hierochloe borealis) hardly reaches the southern end of 

 the Wisconsin drift as it only reaches as far south as Marshall and Ham- 

 ilton counties. This grass, however, can hardly be classed as a real bog 

 species as it is usually found on moist drift soils further northward. 

 A hasty survey certainly shows that the Wisconsin drift has influenced 

 in a marked manner the flora of northern central Iowa. 



A brief list of the plants shows that the sphagnum which constitutes the 

 bulk of the vegetation in the bogs of Wisconsin is entirely lacking in 

 Worth and Cerro Gordo counties, and in place we find Hypnums. The 

 bogs, however, contain a number of most interesting northern plants, 

 among them Spanish needle (Bidens beckii), marsh thistle (Cirsium muti- 

 cum), fringed gentian (Gentiana crinita), gentian (G. quinquelflora, G. 

 andrewsii), parnassas (Parnassia caroliniana), cowbane (Cicuta bulbi- 

 fera), brorne grass (Bromus kalmii), meadow rue (Thalictrum pur- 

 purascenes), pussy willow (Salix discolor, S. richardsonii), bog wil- 

 low (S. Candida). The Salix richardsonii and quaking aspen (Populus 

 tremuloides), are quite conspicuous shrubs. Owing to the deposit of soil 

 through cultivation these bogs are beginning to "dry up," as the common 

 expression is. Scattered throughout the bogs are small groups of Populus 

 tremuloides which in course of time will give rise to a mesophytic 

 forest. In fact, the course of the formation of the forest here is very 

 different than in northern Minnesota. The reason for this is no doubt 

 the lack of forest-forming species in the immediate vicinity, the tamarack 

 and spruce both being absent and no seed anywhere in the vicinity. 



