114 



PRUSSIC ACID IN WILD CHERRY LEAVES 



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Fig. I.— Leaf of Wild Red 

 Cherry. Full size. 



red cherry, " pigeon cherry," known 

 botanically as Prmius Pennsylvanica. 

 This is a shrub, often growing to a 

 small tree, to be recognized by its 

 light, reddish brown bark and waxy, 

 glossy leaves, which are green on 

 both sides, oblong lanceolate in shape, 

 possessing an irregular and sharply 

 serrate Qi\%Q^ the teeth of which are 

 very small and short. (Fig. i.) 



The second species, Prunus Vir- 

 glniana^ commonly known as the 

 choke cherry, is more common than 

 the preceding and its leaves are more 

 poisonous. Like the next species, it 

 is to be found as a constituent of the 

 average roadside thicket throughout 

 New England. It is described by 

 Grav as follows : 



"Tall shrub, or small tree, greyish 

 bark, oval-oblong or obovate and abruptly 

 pointed thin leaves, very sharply serrate 

 with slender projecting teeth (Fig, 2.) ; 

 flowers in shorter and closer racemes (than 

 P. seroiind) in spring ; the fruit ripe in 

 summer, red turning dark crimson, astrin- 

 gent, but eatable when fully ripe." 



It is a noteworthy fact, serviceable 

 as a means of identification, that this variety is usually more 

 or less affected by black knot, which is never to be found upon 

 the two other species. 



By far the most dangerous variety occurring in New Eng- 

 land is the wild black cherry, Prtmus serotlna^ thus des- 

 cribed by Gray : 



" Tree or shrub, westward becoming a good sized forest tree, with 

 bitter aromatic bark, close-grained reddish wood, valued by the cabinet 

 maker; oblong or lance-oblong leaves, thickish or firm texture, usually 

 taper pointed, serrate, with incurved short callous teeth ; flowers in 



