596 TRANS. ST. LOUIS ACAD. SCIENCE. 



** Incluscc-. bracts shorter than the scales. 



2. A. balsamea. 



3. A. subalfina. 



Sec. II. Grandes : Resin ducts close to the epidermis of the lower 

 side, towards the edges ; leaves on lower branches notched or obtuse : on 

 upper obtuse, rarely ever acute ; bracts enclosed. — Two western species. 



4. A. grandis. 



5. A. concolor- 



Sec. III. Bracteat^e : Resin ducts as in last; upper side of the rigid, 

 mostly acute, leaves without stomata, with a continuous layer of hypoderm 

 cells, usually similar cells within the sheath of the fibro-vascular bundle; 

 pallisade-parenchyma very strongly developed; bracts exsert. — A Mexican 

 and a southwestern species. 



6. A. religiosa. 



7. A. bractcata. 



Sec. IV. Nobiles: Leaves of the adult tree and especially of the fer- 

 tile branches quadrangular, short, curved, but scarcely twisted : resin ducts 

 close to the epidermis of the lower side, and equidistant from the edge and 

 keel ; fibro-vascular bundles single ; stomata on both sides ; leaves of young 

 trees much like those of Sec. II. — Two species of the higher mountains of 

 the Pacific slope. 



* Exsert a-, bracts protruding. 

 S. A. nob His. 



** Inclusa ■■ bracts shorter than scales. 

 9. A. magnified. 



1. A. Fraseri [Pinus, Pursh. Fl. 2, 639, 1816; Parlatore in DC. Prod. 

 16, 2, 419), Lindl. Pen. Cyc. 1, No. 5 (1S33), Forbes, Link, etc. This is 

 probably the most local species in the United States, being confined to the 

 tops of the highest mountains of North Carolina, which have an altitude 

 of 6,000 feet or more, and the tops of which it covers together with some 

 Picea nigra, but it never occurs mixed with the following species. — A 

 small tree rarelyas much as 30 or 40 feet high, and 12 or iS inches in diam- 

 eter, probably never more than 60 to 75 years old, with cinnamon-brown 

 smoothishbark; readily distinguished from balsamea by the shorter, more 

 oval cones with largely exsert and refiexed bracts, and always, even when 

 sterile, by the almost uninterrupted stratum of hypodermic cells .on th<_- 

 upper side of the leaf, more crowded on the edges. The white bands on 

 the under side of the leaf consist usually of S or 10, or even 12 series of 

 stomata; heighth of scales (without the stipe) equal to one-half or two- 

 thirds their width; length of seeds equal to length and width of wing. — 

 Forms of the next species with exsert tips of bracts, in the mountains of 

 Pennsylvania, Vermont, and other northern regions, seem to have been 

 mistaken for this species. In eastern as well as in European gardens forms 

 of balsamea are often cultivated under the name of Praseri. 



