MORACEAE 91 



2. Ulmus racemosa Thomas . Cork or rock elm. 

 Ulmus thomasi Sarg. 



Along streams, not common. Meadville; Plattsmoiith; Valentine. 



3. Ulmus fulva Michx. Slippery or red elm. 

 Along streams, a smaller tree and less common than the white elm. 

 Crete; Guide Rock; Red Cloud; Richardson County; Wahoo; Weeping 

 Water. 



2. Celtls. 339. 

 1. Celtis occldentalis L. Hackberry. 



Common throughout the state, mostly along streams. Anselmo; Aten; 

 Banner County; Endicott; Hooker County; O'Neill; Red Cloud; Thed- 

 ford. 



4. MORACEAE. 

 Trees. 1. Morus. 



Vines with lobed leaves. 2. Humulus. 



Herbs with divided leaves. 3. Cannabis. 



1. Morus. 340. 



Leaves rough above, pubescent beneath, fruit purple. 1. M. rubra. 



Leaves smooth and shining, fruit whitish. 2. M. alba. 



1. Morus rubra L. Red mulberry. 



Along streams in the southeastern part of the state. Endicott; Ne- 

 hawka; St. James; Xemaha. 



2. Morus alba L. White or Russian mulberry. 

 Sometimes escapes from cultivation. Weeping Water. 



2. Humulus. 341. 



1. Humulus lupulus L. Hops. 



In woods and thickets throughout the state. Brunswick; Gage County; 

 Holt County; Hooker County; Lincoln; Sioux County; Wahoo. 



3. Cannabis. 341. 



1. Cannabis satiya L. Hemp. 



Sometimes escapes from cultivation. Crete; Long Pine; Lincoln; Red 

 Cloud; Rushville. 



5. URTICACEAE. 



Leaves at least some of them opposite. 



Plants with stinging hairs. 1. Urtica. 



Plants without stinging hairs. 



Calyx of pistillate flowers of 3 sepals, achene 1 mm. long. 



3. Adicea. 

 Calyx of pistillate flowers tubular. 2-4 toothed, achene nearly 2 

 mm. long. 4. Boehmeria. 



Leaves all alternate. 



Flowers in loose axillary cymes, not involucrate, 2. Urticastrum. 

 Flowers glomerate, involucrate. 5. Parietaria. 



1. Urtica. 342. 



Leaves ovate, cordate plant very bristly. 1. U. dioica. 



Leaves lanveolate, rarely cordate, plant sparingly bristly. 



2. U. gracilis. 



