I 



FLOBA OF THE DISTRICT OF COLUMBIA. 179 



Petioles 15 mm. long or longer. 



Leaves wedge-shaped, broadest at or above the middle. 



, Leaves broadest toward the apex; petioles without stalked glands. 



3. C. crus-galli. 

 Leaves broadest at the middle; petioles with stalked glands. 



Leaves, corymbs, and fruit pubescent 4. C. intiicata. 



Leaves, corymbs, and fruit glabrous 6. 0. straminea. 



Leaves broadest at the base. 



Leaves 1.5-6.5 cm. long and wide; calyx lobes usually entire. .6. C. pruinosa. 



Leaves 2.5-10 cm. long and wide; calyx lobes usually toothed...?. 0. coccinea. 



1. Crataegus phaenopyrum (L. f.) Medic. Washington thorn. 

 Fields and roadsides; known from a few localities. May. Md. to Ga. and west- 

 ward. (C. cordata Ait.) 



2. Crataegus uniflora Muenchh. 



Woods along the upper Potomac; occasional. May. Eastern U. S. (C. parvi/olia 

 Ait.; C. tomentosa of Gray's Manual.) 



3. Crataegus crus-galli L. Cockspur, 

 Sandy soil; frequent. May. Eastern N. Amer. 



4. Crataegus intricata Lange. 



Congress Heights and Hunting Creek; rare. May. Eastern U. S. (C. coccinea 

 of Gray's Manual, and of Ward's Flora, in part; probably C. tomentosa of Brereton's 

 Prodromus.) 



5. Crataegus straminea Beadle. 



High Island (Steele). Eastern U. S. (C. apposita Sarg.) 



6. Crataegus pruinosa (Wendl.) Koch. 



Near Laurel (/. B. S. Norton). May. Eastern U. S. 



7. Crataegus coccinea L. 



High Island (Sudworth); without locality (Vasey). Eastern N. Amer. (C. pedi- 

 cellata Sarg.) 



Crataegus monogyna Jacq. was reported from near Alexandria by Ward (as C. oxya- 

 cantha). Native of Eur. and Asia; cultivated and sometimes escaping. 



Crataegus canbyi Sarg., C. cuneiformis (Marsh.) Eggleston, and C. hoyntoni Beadle 

 may occur in our area and should be looked for. 



81. AMYGDAIACEAE. Almond Family. 



Ovary and fruit pubescent; stone pitted , 1 . AM YGDALUS . 



Ovary and fruit glabrous; stone smooth or nearly so 2. PRTJNTJS. 



1. AMYGDALUS L. 

 1. Amygdalus persica L. Peach. 



Occasionally found growing spontaneously in waste land. Apr. Native of Asia. 

 (Prunus persica Stokes.) 



2. PRUNUS L. 



Flowers in racemes, the axis longer than the pedicels. 



Leaves thick, oblong, crenate-serrulate, the teeth incurved 1. P. serotina. 



Leaves thin, obovate, sharply serrate, the teeth somewhat spreading. 



2. P. virginiana. 

 Flowers in umbels or in very short racemes. 

 Flowers large, the petals 8-16 mm. long. 

 Teeth of leaves acuminate, not glandular; fruit oblong-globose, about 2 cm. in 



diameter 3. P. americana . 



Teeth of leaves obtusish, some or all glandular; fruit depressed-globose, about 

 1 cm. in diameter. 



