72 MOKACEAE 



Flowers preceding leaves; fruit a samara. 1. ULMUS. 



Flowers with leaves ; fruit a drupe. 2. CELTIS. 



1. ULMUS L. 



Trees with serrate, strongly-veined, obovate, inequilateral leaves. 

 Flowers perfect or polygamous, fascicled or racemose, on jointed pedicels. 

 Samara winged all around. 



Flowers fascicled. 



Samara ciliate. 1. u. Americana. 



Samara smooth. 3. U. pubescens. 



Flowers racemose. 2. U. racemosa. 



1. U. Americana L. WHITE ELM. Often 120 high ; branches not 

 corky-winged : leaves smoothish above : flowers long-pedicelled. Com- 

 mon along streams. March-April. 



2. U. racemosa Thomas. CORK ELM. Like the last : branches often 

 corky-winged : samaras densely ciliate In rocky woods along the Mis- 

 souri Eiver bluffs from Kansas City to Little Blue River. March-April. 



3. U. pubescens Walt. SLIPPERY ELM. Sometimes 70 high: twigs 

 and bud-scales pubescent : leaves rcugh-pubescent above : flowers short 

 pedicelled. A common forest tree. March-April. 



2. CELTIS Tourn. HACKBERRY. 



Trees with pinnately-veined leaves and axillary polygamous flowers. 

 Starninate flowers clustered. Fertile flowers one or two together and 

 peduncled. Calyx 5-6-parted. Fruit a globular drupe. 



Leaves serrate. 1. C. occidentalis. 



Leaves entire. 2. C. Mississippiensis. 



1. C. occidentalis L. A small pr large tree with ovate or ovate-lance- 

 olate, sharply serrate, inequilateral leaves : drupe 4 // -5 // diameter. 

 Common along streams and bluffs. April-May. 



2. C. Mississippiensis Bosc. A small tree with lanceolate ovate, en- 

 tire or nearly so, leaves : drupe 2| // -3 // in diameter. In bottoms along 

 the Missouri River near Courtney and Sibley and on rocky hills near 

 Westport and Independence. Local. April-May. 



Var. pumila (Pursh) Mackenzie & Bush, n. comb. 3-8 high : leaves 

 less taper pointed and drupe larger. Rocky banks north of Lee's Summit. 

 ( C. pumila Pursh. ) 



FAMILY 33. MORACEAE Lindl. 



Flowers monoecious or dioecious, small, axillary and clustered. Calyx 

 4-5- parted, the stamens as many as its lobes. Ovary 1-celled, superior, 

 1 ovuled. 



Trees or shrubs. 



Leaves serrate. 1. MORUS. 



Leaves entire. 2. TOXYLON. 



A twining vine. 3. HUMULUS. 



An erect herb. 4. CANNABIS. 



