252 



Minnesota Plant Life. 



Elms. Of the elms there are represented in Minnesota three 

 varieties, and one species of hackberry. The elms which are 

 present in the state are the white or American elm, the slippery 

 or red elm, and the rock- or cork-elm. Their flowers are small, 

 clustered or solitary, quite devoid of petals. The ovary is one 

 or two-celled, with a solitary seed. The fruit of the elm is 

 winged. In the hackberry it is a berry-like nut. The seeds 

 have little albumen. The three varieties of elm which occur 

 in Minnesota may be distinguished by the following characters : 

 When the young fruit is very hairy and the branches are without 



FIG. 118. American elm. L,ake Miunetonka. After photograph by Williams. 



corky wings, the tree is the white elm. When the fruit has no 

 hairs, is larger and the twigs are not supplied with corky wings 

 the tree is the slippery or red elm. When the fruit is hairy 

 and the branches are provided with curious flat cork wings, 

 especially prominent on the young twig, the tree is the rock- 

 or cork-elm. All of these occur in similar regions and, together 

 with the basswoods, maples and oaks, form the most abundant 

 growths in the hardwood forests of the central part of the state. 

 Elms are generally to be recognized by the uneven bases of 

 their leaves, by the strong development of the terminal buds 



