192 Nebraska State Horticultural Society. 



the foothills (Pine ridge, and Wild Cat mountains), and from these to 

 the bluffs of the Niobrara, and North Platte rivers. From the latter it 

 spread to scattered stations along the eastern edge of the Great Sand 

 Hill region (Holt, Greeley, Valley, Custer, Lincoln and Franklin 

 counties). 



Basswood or Linden (Tilia ainericana L.). The wing is an ex- 

 tension and enlargement of the bract of the peruncle of the infiores- 

 cence. The several spherical, dry fruits at maturity are attached nearly 

 at right angles to this wing, which is slightly bent and twisted. At 

 maturity the bract carrying the fruits separates at its base from the 

 tree, and when caught by the wind whirls horizontally, carrying its 

 freight of seed-bearing fruits often to a distance of many metres from 

 the parent tree. The linden occurs abundantly in the forests bordering 

 the Missouri river southeast of Nebraska, and it now extends up that 

 river along the eastern edge of the state and along the Niobrara river to 

 Cherry county. It has also extended up the valley of the Blue and Re- 

 publican rivers on the south to Jefferson county, and the Platte river 

 in the central portion of the state, to Nance county. 



The Elm (Ulmus spp.). The flat seed-pods are wingod on their 

 margins so that the surface is increased several times. When ripe they 

 are very light, and are easily carried by the wind to a distance of ten 

 to twenty or more metres from the parent tree. While great numbers 

 ■fall to the ground under the tree, many are carried to a distance equal 

 to or more than that of the height of the tree. 



The White Elm (Ulmus americana L.) is very abundant in the 

 valley of the Missouri river southeast of Nebraska, and thence east- 

 ward to the Atlantic ocean. From the southeastern forest body of this 

 species it has extended up the several river valleys into all portions of 

 the state to the western counties. 



Rock Elm (Ulmus raceniosa Thomas) occurs commonly in the 

 forest belt bordering the Missouri river southeastward, and from this 

 region it has moved upward along the eastern border of the state and 

 up the Niobrara river near the northern boundary. While it has been 

 recorded from but two stations (Cass and Keya Paha counties) it is 

 highly probable that it occurs somewhat sparingly and perhaps inter- 

 mittently along the eastern and northeastern border. 



Red Elm (Ulmus fulva Michx. ) is abundant in the Missouri river 

 forest area, from which it has spread westward up the river valleys 

 nearly or quite half way across the state. Beyond this area a single 

 station is reported in Frontier county. 



The Ashes (Fraxinus spp.). Each cylindrical seed pod is pro- 

 longed upward into a flat oar-shaped, slightly bent and twisted wing. 



