IOWA ACADEMY OF SCIf:NCf:S. 83 



Oa the poor sandy soil lietweeu the Black and La Crosse rivers it is the 

 most common Oak. On clay and rocky soil it occurs mainly in small groups. 

 Some thirty miles east of La Crosse, in the Kickapoo Valley, Bur Oak is a 

 most valuable forest tree. The trunk is straight with but few large lateral 

 branches. In its habit it is wholly unlike the form growing on sandy, rocky 

 soil. Many trees are ten feet in circumference. It does not grow in isolated 

 groups, but acres are covered almost entirely with this species. It also 

 occurs in the rich alluvial bottoms of various streams. The Swamp White 

 Oak((^. bicolor, Willd.) occurs only in the bottoms of the Black and Mississippi 

 rivers. A large number of small trees occur near North Bend, Wisconsin. 

 I have observed a few more just below La Crosse. It becomes moi'e com- 

 mon southward; and a considerable number were observed near Turkey 

 River Junction, Iowa. No large trees have been seen, though Mr. J. S. 

 Harris informs me that he noticed some near La Crescent, Minnesota, many 

 years ago. The only other Oak I have seen is Q. Muhlenbergii, Eugelm. It 

 occurred in considerable numbers on the south slope of a limestone blulT 

 just west of North Mc(Jregor, Iowa. 



The most conspicuous Maple is the Soft Maple (Acer saccharimim, L.) It 

 occurs everywhere along the Mississippi, Black and Wisconsin rivers and 

 their tributaries. It forms more than one-half of the forest vegetation of 

 the Mississippi rivei', but becomes less common as the sources of the smaller 

 streams are reached. It gi'ows where the lands are usually subject to over- 

 flow, and the soil is sandy or alluvial. The Red Maple (Acer rubriim, L.) is 

 not a common species. It occurs in the interior of the country, away from 

 the Mississippi, on the black, sandy loam. Although the Sugar Maple [Acer 

 barbamm, Michx.) occurs in the rich, rocky soil aloug the Mississippi river, it 

 is most common in the interior of Wisconsin, away from the river. On low 

 ridges drained by the Kickapoo river it is one of the most common of forest 

 trees. 



Acer spicatum Lam., although not a forest tree, deserves mention. It 

 grows in sheltered situations, frequently overhanging sandy rocks, about 

 La Crosse and Galesville. Between Dubuque and McGregor, Iowa, it grows 

 in shaded, moist situations, in calcareous soils, commonly with Sambticns 

 raeemosa, L. 



The Ash-leaved Maple (Acer negimdo, L.) occurs in groups in the richer 

 soils of ravines and bottom lands; it is seldom found in the bottom proper 

 of the Mississippi river. 



Two species of Hickory have been observed. Shell Bark [Hicoria ovata) 

 and the Pignut Hickory (H. glabra. Mill., Brittou). Both species attain 

 considerable size. The habits of the trees are quite different. H. ovata 

 grows on clay soil, usually in groups. H. glabra grows on various 

 soils, such as rocky, sandy, and along creek-bottoms. Shaded and moist 

 localities are favorable to its growth, which is much more rapid than that 

 of E. ovata. The Butternut (Juglans cinerca L.) is much more com- 

 mon than the Black Walnut (•/. nigra, L.), although both are found on the 

 rocky banks of the Mississippi, and the Butternut is abundant in sandy and 

 gravelly -soil aloug the Kickapoo river, while Black Walnut was not ob- 

 served iu this region. The latter tree is confined quite closely to the imme- 

 diate tributaries of the Mississippi. Along the Badaxe river and smaller 

 streams about La Crosse it is quite common, but as the sources of the stream 



