ANACARDIACEAE 155 



3. Acer negundo L. Boxelder. 



Common all over the state, mostly along streams. Anselmo; Lincoln; 

 Nebraska City; Norway. 



3. ANACARDIACEAE. 



Rhus. 602. 



Leaves pinnate, leaflets 9 or more. 



Leaflets pinnate or nearly so, rachis wing margined. 1. R. copal Una. 

 Leaflets sharply serrate, rachis not winged. 2. R. glabra. 



Leaves trifoliate. 



Leaflets 3-lobed, 1.5-2.5 cm. long, fruit pubescent. 3. R. trilobata. 



Leaflets mostly entire, 3-10 cm. long, fruit glabrous. 



Vines climbing by aerial roots, or trailing, rarely suberect, fruit 

 about 4 mm. in diameter. 4. R. radicans. 



Shrubs without aerial roots, fruit 5-6 mm. in diameter, 



5. R. rydbergii. 



1. Rhus copallina L. Dwarf or Black Sumach. 

 In the extreme southeastern part of the state. Nemaha; Richardson 

 County; Rulo. 



2. Rhus glabra L. Smooth or Scarlet Sumach. 

 Common throughout the state. (Our western forms from Aten, An- 

 selmo. Plummer Ford and Thedford m.ay belong to Rhus cismontana 

 Greene.) Anselmo; Aten; Emerald; Fairbury; Lincoln; Nebraska 

 City; Plumm.er Ford; Thedford. 



3. Rhus trilobata Nutt. 



Common in the western part of the state. Arapahoe; Belmont; Deuel 

 County; Herrick; Long Pine; Pine Ridge; Thedford; Valentine. 



4. Rhus radicans L. Poison Ivy. 

 Common in woods and along fences. Lincoln. 



5. Rhus rydbergii Small. Western Poison Ivy. 

 In open woods and prairies. Kearney; Long Pine; Minden; Newcastle; 

 Valentine. 



4. JUGLANDACEAE. 



Husk not dehiscent, nut rough, leaflets 11-23. 1. Juglans. 



Husk dehiscent, nuts smooth or angled, leaflets (in our species) 3-9. 



2. Hicoria. 



1. Juglans. 323. 



Fruits globose, twigs and petioles pubesulent, dark brown and rough. 



1. J. nigra. 



Fruits elongated, twigs and petioles viscid pubescent, bark gray, 



smoother, 2. J. cinerea. 



1. Juglans nigra L. Black Walnut. 

 Along streams mostly in the eastern part of the state. Lincoln; Long 

 Pine; Naponee; Nebraska City; Wahoo; Wymore. 



2. Juglans cinerea L. Butter Nut. 

 Found sparingly in the southeastern part of the state. Nebraska City; 

 Weeping Water; Wymore. 



