FLORA OF THE DISTRICT OF COLUMBIA. 141 



1. TJlmus americana L. American elm. 

 Low woods and along streams; also planted along our streets. March; fr. Apr. 



Eastern U. S. 



2. Ulmus fulva Michx. Red elm. 

 Low woods and along streams; also in cultivation. March; fr. Apr. Eastern U. S. 

 Known also as slippery elm. 



Ulmus campestris L. the English elm, from western Europe, is frequently planted. 

 Petioles 5 mm. long or more; blades 5-7.5 cm. long, oval or ovate, short-acuminate, 

 scabrous above, pubescent beneath; fruit nearly orbicular, 10 mm. broad or more, 

 the seed touching the notch. 



2. CELTIS L. Hackberry. 



Leaves mostly entire, ovate-lanceolate, acuminate, 6 cm. long and 4 cm. wide or 



smaller, glabrous on the upper surface 1. C. mississippiensis. 



Leaves serrate, of a broader type, mostly acute. 



Leaves glabrous or nearly so on the upper surface 2. C. occiden talis. 



Leaves rough on the upper surface 3.0. crassifolia. 



1. Celtis mississippiensis Bosc. 



Near Anacostia (Painter). Southern states, north to Va. 



2. Celtis occidentalis L. 



Rocky soil and dry woods. May; fr. Sept.-Oct. Northern states, south to N. C. 



3. Celtis crassifolia Lam. 



Potomac Valley above Georgetown. May; fr. Sept.-Oct. Northern states, south 

 to S. C. 



40. MORACEAE. Mulberry Family. 



Ficus carica L., the common fig, is often found in waste ground, especially about 

 Alexandria. 



Leaves entire, ovate to oblong-lanceolate, acuminate; staminate flowers in long- 

 stalked racemes. Pistillate flowers in globose heads; fruit yellowish green, 10 



cm. in diameter or less 1. TOXYLON. 



Leaves toothed or lobed; staminate flowers in spikes. 



Twigs hirsute; fruit in globose heads 2 cm. in diameter, not edible, on short stout 

 peduncles. Leaves rough above, velvety beneath, ovate-lanceolate, serrate 



or 2-3-lobed 2. PAPYRITJS. 



Twigs glabrous or pubescent; fruit aggregate, oblong, edible 3. MORUS. 



1. TOXYLON Raf. 

 1. Toxylon pomiferum Raf. Osage orange. 



Escaped from cultivation. May. Native farther west. (Madura aurantiaca 

 Nutt. ; M. pomifera C. Schneid.) 



2. PAPYRIUS Lam. 



1. Papyrius papyrifera (L.) Kuntze. Paper mulberry. 



Escaped from cultivation; forming thickets. May. Native of the Pacific Islands. 

 (Broussonetia papyri/era Vent.) 



3. MORUS L. Mulberry. 



Leaves cordate-ovate, smooth, glabrous or nearly so; fruit white, 1-1.5 cm. long. 



1. M. alba. 



Leaves obliquely ovate, rough above, pubescent beneath; fruit purple, 2 cm. long 



or more 2. M. rubra. 



1. Morus alba L. White mulberry. 

 Escaped from cultivation. May. Native of western Asia and Eur. 



2. Morus rubra L. Red mulberry. 

 Low woods. May. Eastern U. S. 



