BOTANICAL DESCRIPTION. 49 



BOOT, STEM, AND BUANCH SYSTEM. 



The Long-leaf Piue attains a height averaging 100 feet, rarely exceeding 110 feet, with a 

 diameter breast high, when fully grown, varying between 20 and 3G inches, rarely more. The 

 tall, straight, very gradually tapering trunk arises from a massive taproot which, in favorable 

 situations, penetrates the soil to a depth of from 12 to 15 feet, and sometimes much more. It 

 has several stout, comparatively short lateral roots, which assist the tree in its hold by slant- 

 ing deeply into the ground, and some of greater length are placed more or less near the surface. 

 Its crown is open and elongated, of irregular shape, about one half to one third of its height. 

 The stout limbs are rarely over 20 feet in length, twisted and gnarled and sparingly branched. 

 The trunk is covered with a reddish-brown bark, one-fourth to three-fourths of an inch thick, 

 furrowed throughout its full length, crossed horizontally by deep fissures, and scaling oft' in thin, 

 bluish, almost transparent ihombic Hakes. 



LEAVES AND THEIR MODIFICATIONS. 



Like all the pines, this species produces during various stages of its growth seven different 

 modifications of leaves as recognized by botanists, all more or less specific in character: 



(1) Cotyledonary, or seed leaves (first leaves of the embryo), which soon wither and disappear 

 (PI. VII, a, h). (2) Primary leaves succeeding the former immediately on the main axis (PI. VII, c), 

 which either wither or later on are transformed into, or succeeded by, more or less permanent 

 bracts or scales covering the branches (PI. V, «). (3) The secondary or foliage leaves rising from 

 the buds produced in the axils of the primary leaves or of the scales by which they are represented 

 (PI. VII, d), forming the permanent foliage of the tree, with three leaves in one sheath. (4) The 

 bud scales forming the sheaths of the foliage leaves (PI. IV, 1>, c, c1) at base. (5) Involuci-al bracts 

 of the male flower (PI. V,_/'). (6) luvolucral scales of the female inflorescence (ament) (PI. V, e). 

 (7) The bracts which support the carpellary scale bearing the seed (PI. V, /»).' 



The primary leaves, which succeed the cotyledons on the i)rimary axis, are in form and structure 

 true leaves. They are softer than the final foliage leaves, have a broad base, are rounded on the 

 dorsal side and not channeled, the whitish transparent margins being finely \)ut distinctly den- 

 ticulate. It is rare that secondary leaves proceed from the axils of these chlorophyll-bearing 

 primary leaves. With the more frequent appearance of the ordinary leaves, these primary leaves 

 wither and henceforth appear as triangular scale like coriaceous persistent bracts, with broad, 

 hyaline, long-fringed edges, in the axils of which the undeveloped branchJets are produced bearing 

 the secondary or foliage leaves. 



Tlie cidorophyll-beariiig primary leaves exhibit a simple structure. The flbro-vascular bundle 

 is single, embedded in a wider ring of large cells free from chlorophyll, and the resinous ducts fewer 

 iu number, one, or rarely more than two, being irregularly situated in the clilorophyll-beariug 

 parenchymatous tissues, and mostly external, i. e., close to the thick epidermis. But few of these 

 leaves are formed after the appearance of the foliage leaves, and a few of them persist thi-oughout 

 the first season.- The cataphyllary leaves forming the sheath or the foliage leaves are iu this 

 si)ecies composed of eight successive jiairs of bud scales; those of the first pair are blunt, fiat, 

 deeply concave and coriaceous, with sharp edges; the others are more membranaceous and with 

 ringed edges, the closely interwoven edges entwining the base of the fascicle. In the secondary 

 leaves the very numerous stomata form, on both sides, regular longitudinal rows. Parallel with 

 these, at regular distances between them and embedded iu the parenchymatous tissue, are found 

 bundles of numerous, elongated, thick-walled cells, the so-called hypodermal or strengthening cells. 

 The resin ducts, not over five in number, described bj Engelniann as internal, have been found in 

 the specimen examined rather parenchymatous, invariably so on the dorsal side. 



Three of the secondary or true foliage leaves are united into one bundle, inclosed at the base 

 by a persistent sheath from one-half inch to an inch in length, formed by the bud scales or 

 cataphyllary leaves. On the older trees the leaves are rarely over 8 inches in length, but during 

 the periods of most active growth they are found 12 to 18 inches long. They are finely serrulate, 

 rounded on the back, channeled, and obtusely triangular in cross section. 



' George Engelmauu : Revision of the Genus Pinus. Transactions of the St. Louis Academy of Science, 1882. 

 •Engelmann: Revision of Genus Pinus. Trans. St. Louis Academy of Science, 1882, p. 5. 



25666— No. 13—02 4 



