l88 TRANS. ST. LOUIS ACAD. SCIENCE. 



regularly laminated, and the outer laminse exfoliate in rather rigid 

 and brittle, often very thin, plates of a purplish color when freshi 

 whence the local name of Blue Pine ; the bark of P. australis is 

 somewhat similar, but the plates are much larger. 



The timber is excellent, heavy, very tough, and more resinous 

 even than that of P. australis, which it resembles ; of a striped 

 yellowish -brown and paler resin color (the inner portion of 

 each ring, formed earlier in the season, being paler ; the outer 

 part, of later growth, brown) ; fibre coarser than in australis 

 and more tenacious. It grows rapidly, at least in its youth : 

 a tree of 22 inches diameter, and about 140 years old, had in the 

 semi-diameter 8j inches of heartwood with 74 annual rings, and 

 white sapwood z\ inches thick with 60 to 70 rings ; another 

 of over 3 feet diameter, 109 feet high, and 200 years old, had a 

 radius of 17 inches heartwood with about 140 rings, and 3 inches 

 of sapwood of 60 rings. Thus the average rings of the heartwood 

 were over li lines and those of the sapwood (because of later 

 growth) about 2 line wide. The leaves of young trees are more 

 frequently in twos, in older ones as often in threes : those of trees 

 from swampy soil are apt to be shorter than others ; the structure 

 in all of them is the same. 



Our species is closely allied to P. Ciibetisis (see p. 185), and 

 further study of the latter may possibly prove them to be nothing 

 but geographical varieties. Meanwhile the constantly three-leaved 

 foliage, the larger number of involucral bracts of the smaller male 

 flowers, the smaller cones with smaller, shorter-winged seeds, 

 distinguish P. Cvbensis from our species. Of the bark, of the 

 timber, or of the behaviour of the young cones in this species we 

 know nothing. 



P. Elliottii was imperfectly known to Elliott, and was consid- 

 ered by him a form of P. Tceda. Later botanists ignored it till Dr. 

 J. H. Mellichamp of Bluflton, S. Car., rediscovered it about ten 

 years ago and directed my attention to it. Without his diligent 

 investigations, ample information, and copious specimens, this 

 paper could not have been written. At the same time I grate- 

 fully acknowledge my obligations to many botanical friends in 

 this country and in Europe, and especially to the directors of the 



