194 Class XII. Order III. 



last year's branches, in numerous umbels of from two to five 

 flowers. Peduncles short, filiform, pubescent under a magnifier 

 as well as the calyx. Corolla small, white. Fruit large, globu- 

 lar, eatable, with the flavour of the common plum. Always near 

 the salt water ; abundant on Plum island. May. Fruit ripe in 

 August and September. 



Variety . Fruit an inch in diameter, purple, with a glaucous 



bloom. 



/3. Fruit similar but smaller. 

 y. Fruit crimson, shining. 



This is our common Beach plum, much prized for its agreea- 

 ble fruit, and deserving attempts at cultivation. I do not find it 

 described by any author, unless possibly by Michaux under the 

 name of P. sphaerocarpa, a name previously appropriated by 

 Swartz to a West Indian species. From P. maritima of Pursh it 

 appears widely different in its inflorescence, acumination, and 

 fruit. 



DIGYNM. 



200. CRAT^EGUS. 



CRATJEGUS CRUS GALLI. L. Common Thorn Bush, 



Thorny ; leaves obovate, snbsessile, shining, coria- 

 ceous ; leafets of calyx lanceolate, subserrate. Ait. abr. 



A strong, branching, thorny shrub. Leaves inversely ovate, 

 sharply and irregularly serrate, sometimes cleft, tough, smooth. 

 Thorns two or three inches long, rigid, acute. Flowers white, 

 in terminal corymbs. Calyx leaves linear. About fences and 

 thickets. May, June. 



TR1GYNM. 



201. SORBUS. 



SORBUS AMERICANA. JWuhl. Mountain Ash. 



Leaves pinnate, leafets glabrous, acute, subequally 

 serrate, petioles glabrous. 



yn. SORBUS AUCUPARIA, /3. MX. 



