ENGELMANN AMER. JUNIPERS OF SEC. SABINA. 583 



The American Junipers of the section Sabina. 



By Dr. George Exgelmann. 



The species of our Junipers, are, on the whole, well enough 

 recognized, but their scientific definition is very insufficient — the 

 characters, given in the books, vague and indefinite. 



I have had a good opportunity to study the different species 

 and forms from all parts of our country, fresh and living as well 

 as preserved in numerous collections ; among them those con- 

 tained in the great Herbaria of New York and Cambridge (Tor- 

 rey and Gray) and those of Kew (Hooker), and especially those 

 of Berlin, whence the types of the different Mexican species were 

 sent to me by my late excellent friend, Alexander Braun. 



With the exception of fu/iiperus Sabina, which with us is al- 

 ways a prostrate plant, all our species occur both in the form of 

 low shrubs or of trees, a few of them of magnificent dimensions. 

 In the arid mountain regions, the trunks of the different species 

 which occur there frequently assume peculiar conical forms, very 

 thick at base and rapidly tapering to a slender point. 



The bark is in most species thin, fibrous, and at last detached 

 in shreds; only in y. pachyphkva it is 1-3 inches thick, cracked 

 like that of some oak or chestnut, the surface at last pealing oft' 

 in thin layers. 



The wood is fine-grained and compact but not always hard ; 

 its growth is very slow, so that trees of 200 years have a diameter 

 of 4-6, or, in the species growing in more generous soil and a 

 more favorable climate, of 13-18 inches. Therefore, when we 

 hear of mountain forms (necessarily of slow growth) having near 

 their base a diameter of 3 feet, we cannot help estimating their 

 age* at a thousand years and upwards. In J. occidentalis the 

 annual rings are often quite eccentric. The resin is confined to 

 the cambium layer and the inner bark ; the wood is quite free 

 from it but extremely durable, and, at least in J. Virginiana, 

 almost indestructible. In this species the heartwood is red (hence 

 the name Red Cedar) and very aromatic, soft, and splitting easily ; 



* This is also alluded to in a letter received, alter the above was in type, from Sir J. D. 

 Hooker, who had just returned from an exploration of our western mountain regions, in 

 which he speaks of the " stupendous age " of their Junipers, meaning probably J. occi. 

 doit a I is. 



