CONIFERS. (PINE FAMILY.) 469 



1. PINUS, Tourn. Pine. 



Sterile catkins arranged in a spike at the base of the shoot of the same spring, 

 involucrate by a nearly definite number of scales, consisting of numerous sta- 

 mens spirally inserted on the axis, with very short filaments and a scale-like 

 connective : anther-cells 2, opening lengthwise. Pollen of 3 united grains. 

 Fertile catkins solitary or aggregated immediately below the terminal bud, or 

 lateral on the young shoot, consisting of imbricated carpellary scales, each in 

 the axil of a persistent bract, bearing a pair of inverted ovules at the base. 

 Fruit a cone formed of the imbricated and woody carpellary scales, which are 

 Ihickened at the apex (except in White Pines), persistent, spreading when ripe 

 and dry ; the 2 nut-like seeds partly sunk in excavations at the base of the scale, 

 and in separating carrying away a part of its lining in the form of a thin and 

 fragile wing. Cotyledons 3- 12, linear. — Primary leaves of the shoots thin 

 and chaff-like, merely bud-scales ; from their axils immediately proceed the 

 secondary leaves, which make the foliage, in the form of fascicles of 2 to 5 needle- 

 shaped evergreen leaves, from slender buds, some thin scarious bud scales sheath- 

 ing the base of the cluster. When there are only 2 leaves in the cluster they 

 are semicylindrical and when dry channelled or concave ; when more than 2 

 triangular; their edges in our species serrulate. Blossoms developed in spring; 

 the cones maturing only in the autumn of the second year. (The classical 

 Latin name.) 



The species here arranged and characterized from notes contributed by Dr. 

 Engelmann. 



§ 1. Leaves 2 or 3 in a close sheath : cones (except in No. 7) persistent after shedding 



the seed ; their woody scales thickened at the end, and usually spiny-tipped. 



* Fertile catkins and cones lateral: scales much thickened at the end : leaves rigid. 



-h- Leaves in threes. 



1. P. Tsbda, L. (Loblolly or Old-field Pine.) Leaves long (6'- 10'), 

 with elongated sheaths, light green; cones elongated-oblong (3'- 5' long) and 

 tapering ; scales tipped with a stout incurved spine. — Barren light soil, Delaware 

 ( W. M. Canby), Virginia, and southward near the coast. — Tree 50° - 100° high. 

 Sterile catkins slender, 2' long, their involucre of 10-13 (rarely fewer) scales. 

 Seeds with 3 strong and rough ridges on the under side : cotyledons 5-8. 



2. P. rigida, Miller. (Pitch Pine.) Leaves (3' -5' long) dark green, 

 from short sheaths; cones ovoid-conical or ovate (l'-3^' long), often in clusters; 

 the scales tipped with a short and stout recurved prickle. — Sandy or spare rocky 

 soil, Maine to W. New York and southward: common. — Tree 30° -70° high, 

 with very rough and dark bark, and hard resinous wood. Sterile catkins slen- 

 der (jr'-lj' long), with 6-8 involucral scales. Seed with hardly any ridges : 

 cotyledons about 5. 



-t- -.'- Leaves in twos, or some of them in threes in 3 $"6. 



3. P. pungens, Michx. (Table Mountain Pine.) Leaves stout, short 

 (l^'-2^-' long), crowded, bluish, the sheath short (very short on old foliage); 

 cones ovate [3$ long), the scales armed with a strong hooked spine (\ ! long). — 

 Alleghany Mountains, especially in the Blue Ridge, N. Carolina and Virginia 



