128 SILVA OF NORTH AMERICA. conifers. 



inches long, from an inch to an inch and a quarter wide, and nearly sessile or short-stalked, with concave 

 scales rounded at the apex, their exposed portions being conspicuously transversely keeled and thickened 

 into central knobs terminating in elevated transversely flattened umbos armed with short stout straight 

 or recurved spines which mostly disappear before the cones open ; turning dark reddish brown, some of 

 the cones open as soon as they are ripe, some remain closed for three or four years before liberating 

 their seeds, ultimately turning to an ashy gray color, and others, while still unopened, become in time 

 enveloped by the growing tissues of the trunk or branches, which finally cover them unless fire in 

 killing the tree opens their scales and scatters their seeds. The seeds are nearly triangular, compressed, 

 and about a quarter of an inch long, with a black slightly tuberculate coat and an embryo with from 

 four to six cotyledons ; their wings are thin and fragile, widest near or below the middle, dark red- 

 brown, lustrous, three quarters of an inch long and about one quarter of an inch wide. 



Pinus clausa, which was first noticed in 1846 near Apalachicola, Florida, 1 by Dr. A. W. Chapman, 2 

 is distributed along the coast of the Gulf of Mexico from southeastern Alabama 3 to the shores of Pease 

 Creek, Florida, seldom extending thirty miles inland ; and in east Florida, from the neighborhood of St. 

 Augustine to Halifax River, it occupies a narrow belt rarely more than a mile wide parallel with and 

 not far from the coast, and ranges southward on sandy ridges to below Jupiter Inlet, where it covers 

 sandy wind-swept plains. On the Gulf coast it is common on the sand dunes of Pensacola Bay, on 

 the shores of Santa Rosa Sound and Choctawhatchee Bay and on Cedar Keys, and flourishes on pure 

 white drifting sands, although it is rarely more than twenty feet high, and bent low in the direction of 

 the prevailing winds is often nearly prostrate ; farther inland, on the dry ridges in the neighborhood of 

 Pensacola and on uplands of better quality, where it grows with Magnolias, Hickories, Live Oaks, 

 and Post Oaks, it is more vigorous, and often of a large size, probably attaining, however, its greatest 

 development on the east coast near the head of Halifax River, where trees from seventy to eighty feet 

 high, with trunks two feet in diameter, are abundant. 4 



The wood of Pinus clausa is light, soft, not strong, and brittle ; it is light orange-color or yellow, 

 with thick nearly white sapwood, and contains broad very resinous conspicuous bands of small summer 

 cells, numerous prominent resin passages, and many thin medullary rays. The specific gravity of the 

 absolutely dry wood is 0.5576, a cubic foot weighing 34.75 pounds. 5 



The stems are occasionally used for the masts of small vessels. The chief value of Pinus clausa 

 consists, however, in its ability to grow rapidly on the barren sands of the hot southern coast, and this 

 tree will probably be found useful if it ever becomes necessary to protect their shifting surface with a 

 forest-covering. 



1 The Pinus Abies Virginiana, conis parvis subrotundis, or the balm 4 Mohr, Garden and Forest, iii. 402. 



of Gilead pine which Bernard Romans saw on the coast of West 5 Pinus clausa grows very rapidly even in pure sand. The log 



Florida in December, 1771, is perhaps this species. (See Nat. specimen in the Jesup Collection of North American Woods in the 



Hist. Florida, 317.) American Museum of Natural History, New York, is thirteen inches 



See vu. 110. an( j a half in diameter inside the bark, and only thirty-nine years 



3 The most westerly station for this tree noticed by Dr. Charles old, its sapwood being two inches and one eighth in thickness, with 



Mohr is between Bon Secour and Perdido Bay in the extreme sixteen layers of annual growth, 

 southeastern part of Baldwin County, Alabama. 



