Plant Migration Studies 15 



ROLLING BALLS 



Sycamore {Plataiuis occidcntalis L.). The flowers grow in 

 spherical heads, and produce compact, spherical clusters of ob- 

 long nutlets, which hang from long peduncles. When they fall 

 from the tree (in the winter) they roll over the ground in the 

 wind, carrying their seeds with them. These trees are common 

 in the forests of Missouri, from wdiich they have moved up along 

 the eastern edge of the state to Douglas County (37). 



EDIBLE SEEDS AND NUTS 



Buckeye (Acscitlus glabra Willd.). The large brown shiny 

 seeds drop to the ground as soon as mature, where they are quite 

 conspicuous. Here they are picked up by large animals and 

 sometimes swallowed. They are too hard to be easily masti- 

 cated, and many must be rejected after trial. In the meantime 

 they have usually been carried some distance from the parent 

 tree. This species occurs in the Missouri forests, from which it 

 has moved into Nebraska (41) as far as Richardson, Pawnee, 

 and Nemaha counties. 



Walnuts (Juglans spp.). The large drupaceous fruits contain 

 a bony shell (the nut) enclosing a four-lobed, edible seed. At 

 maturity the bitter flesh rots away, leaving the nut, which is. 

 picked up by squirrels and related rodents, and carried a\vay to 

 be eaten at once, or hidden for future eating. Many of these are 

 dropped on the way, or those hidden are forgotten or overlooked, 

 so that much eflfective distribution of seeds has taken place. 



Butternut (Jnglaiis cinerea L.) is common in the Missouri 

 forests, from which it has been carried into the southeastern part 

 of Nebraska, as far as Gage, Tohnson. Otoe and Cass counties 

 (46). 



Walnut (Jitglans nigra L.) is found in abundance in the for- 

 ests in the ATissouri River valley southeast of Nebraska, and 

 from here it has moved up that river and up the Niobrara valley 

 to Cherry County. It has occupied the southeastern corner of the 

 state, and the Republican valley to Harlan County (47). 



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