The Migration of Our Forest Trees. 199 



occurs as far west as Franklin county in the Republican valley, and Holt 

 county along the Niobrara rivei-. It has also passed up the Nemaha and 

 the Blue rivers'to Gage and Lancaster counties. 



Buckthorns (Rhamnus spp.). The small drupe contains two to 

 four very hard one-seeded stones, surrounded by a thin flesh. When 

 these drupes are eaten by birds the seeds are preserved from injury by 

 their hard covering. 



Buckthorn (Khainiuis lanccolata Pursh) is common in the Mis- 

 souri forests, from which it has moved up along the eastern border of 

 the state to Cherry county on the Niobrara river. It has followed the 

 tributaries of the Missouri river (Nemaha and Blue rivers) to Gage, and, 

 (Platte river) Saunders counties. 



Indian Cherry (Rhamnus caroliniana Walt.) occurs somewhat 

 sparingly in the Missouri forests, from which it has advanced into east- 

 ern Nebraska, having been noticed at two stations (Cass and Saunders 

 counties). 



Buffalo Berry ( Lei)argyraea argentea (Pursh) Greene.) The small 

 red or amber one-seeded drupes are edible, and are eaten by birds and 

 thus carried away. The seed is protected from injury in the alimentary 

 canal by its hard covering. This small tree is a native of the Rockj 

 mountain region and westward, from which it has been carried eastwp.vl 

 across the state to the banks of the Missouri river (Nemaha county). 



Sumach (Rhus copallina L.). The small one-seeded drupes are 

 crimson in color and have an icid. flavor. They are eaten by birds, and 

 their seeds are protected from injury by the bony seed coat. This 

 ppecies occurs in the Missouri forests, and has been carried northwari 

 to the extreme southeastern corner of the state (Richardson county). 



ROLLING BALLS. 



Sycamore (Platanus occidentalis L.). The flowers grow in spheri- 

 cal heads, and produce compact, spherical clusters of oblong nutlets, 

 "Which hang from long peduncles. When they fall from the tree (in 

 tiie winter) they roll over the groaui in the wind, c.rijlcg their seeJi 

 with them. These trees are common in the forests of Missouri, from 

 which they have moved up along the eastern edge of the state to 

 Doui^las coiinly. 



EDIBLE SEEDS AND NUTS. 



Buckeye (Aesculus glabra Willd.). The large, brown, shiny 

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



