Cones dehiscent at maturity 52. virginiana Cones serotinous 53. clausa Leaves ternate.

Cones dehiscent at maturity 54. rigida Cones serotinous 55. serotina Cones with stout spines 56. pungens Cones oblique or unsymmetrical.

Cones and leaves very short, not exceeding 6 cm.

Cones curved or warped 57. Banksiana Cones straight 58. contorta Cones and leaves much longer, more than 7 cm.

Posterior cone-scales gradually larger than anterior scales.

Bark-formation late 59. Greggii Bark-formation early 60. patula Posterior cone-scales abruptly larger than anterior scales.

Cones with very stout spines 61. muricata Cones with minute or deciduous p.r.i.c.kles.

Bark-formation late 62. attenuata Bark-formation early 63. radiata

48. PINUS PRINGLEI

1905 P. Pringlei Shaw in Sargent, Trees & Shrubs, i. 211, t. 100.

Spring-shoots uninodal, sometimes pruinose. Leaves ternate, from 15 to 25 cm. long; resin-ducts internal or with an occasional septal duct, hypoderm biform, in thick ma.s.ses, often projecting far into the green tissue and sometimes touching the endoderm. Conelets mucronate. Cones from 5 to 10 cm. long, reflexed on a rigid peduncle, subsymmetrical or more or less oblique, tenaciously persistent, often serotinous; apophyses subl.u.s.trous tawny yellow or fulvous brown, convex, the posterior scales often more prominently developed, the mucro usually wanting; seed with a perceptibly thickened wing-blade.

A tree with long erect bright green foliage, confined, so far as known, to the subtropical alt.i.tudes of western Mexico. As it grows in Uruapan, Michoacan, there are two forms of the cone, large and small, both with the same long rigid leaf.

Plate x.x.xI.

Figs. 268, 269. Three cones and seed. Fig. 270, Leaf-fascicle and magnified leaf-section.

49. PINUS OOCARPA

1838 P. oocarpa Schiede in Linnaea, xii. 491.

1842 P. oocarpoides Lindley ex Loudon, Encycl. 1118.

Spring-shoots uninodal, pruinose. Leaves in fascicles of 3, 4 or 5, from 15 to 30 cm. long, erect; resin-ducts mostly septal, sometimes internal, hypoderm biform or multiform. Conelets on very long peduncles, mucronate. Cones from 4 to 10 cm. long, long-pedunculate, broad-ovate to ovate-conic, symmetrical or sometimes oblique, persistent, more or less serotinous; apophysis gray-yellow or greenish yellow of high l.u.s.tre, flat or variously convex, delicately and radially carinate, the umbo often salient, the p.r.i.c.kle usually broken away; seed-wing appreciably thickened at the base of the blade.

A subtropical species, ranging from Guatemala to the northern border of Sinaloa in northern Mexico; remarkable for the length of the peduncle of the cone and for the prevalence of septal resin-ducts in the leaf.

Plate x.x.xI.

Fig. 271, Three cones and seed. Fig. 272, Leaf-fascicle and magnified leaf-section. Fig. 273, Cone from northern part of the range. Fig. 274, Leaf-fascicle and magnified leaf-section from near the northern limit.

[Ill.u.s.tration: PLATE x.x.xI. P. PRINGLEI (268-270), OOCARPA (271-274)]

50. PINUS HALEPENSIS

1762 P. sylvestris Gouan, Hort. Reg. Monspel. 494 (not Linnaeus).

1768 P. halepensis Miller, Gard. Dict. ed. 8.

1803 P. maritima Lambert, Gen. Pin. i. 13, t. 10.

1812 P. resinosa Loiseleur, Nouv. Duham. v. 237, t. 77 (not Aiton).

1815 P. brutia Tenore, Cat. Hort. Neap. Appx. 1, 75.

1826 P. arabica Sieber ex Sprengel, Syst. Veg. iii. 886.

1833 P. pyrenaica David in Ann. Soc. Hort. Paris, 186 (not Lapeyrouse).

1834 P. hispanica Cook, Sketches in Spain, ii. 337.

1838 P. pityusa Steven in Bull. Soc. Nat. Mosc. xi. 49.

1841 P. carica Don in Ann. Mag. Nat. Hist. vii. 459.

1847 P. persica Strangways ex Endlicher, Syn. Conif. 157.

1855 P. abasica Carriere, Trait. Conif. 352.

1855 P. Loiseleuriana Carriere, Trait. Conif. 382.

1856 P. Parolinii Visiani in Mem. Ist. Venet. vi. 243, t. 1.

1902 P. eldarica Medwejew in Act. Hort. Tiflis. vi-2, 21, f.

Spring-shoots often multinodal. Bark-formation late, the branches ashen gray and smooth for several years. Leaves binate, from 6 to 15 cm. long; resin-ducts external, hypoderm uniform. Conelets obscurely mucronate near the apex. Cones from 8 to 12 cm. long, ovate-conic, symmetrical or subsymmetrical, persistent, often serotinous; apophyses red with a lighter or deeper brownish shade, l.u.s.trous, flat, convex or low-pyramidal, radially carinate, the umbo often ashen gray and unarmed.

A tree ranging from Portugal to Afghanistan, and from Algeria to Dalmatia and to northern Italy and Southern France. It is a vigorous species in its own home, growing readily in poor soils, but not successful in colder climates. The wood is resinous and valuable for fuel. The turpentine industry, once a.s.sociated with this species, has gradually been abandoned for the more copious product of P. pinaster.

It is recognized by its l.u.s.trous red cones and by the ashen gray cortex of its branches and upper trunk. Tenore's P. brutia (pyrenaica of some authors) is founded on a difference in the length of the leaf and on an erect cone with a shorter peduncle. To recognize species on such distinctions would not be consistent with the purpose and spirit of this discussion.

Plate x.x.xII.

Fig. 279, Two cones. Fig. 280, Cone. Fig. 281, Lateral conelet. Fig.

282, Magnified leaf-section. Fig. 283, Dermal tissues of the leaf magnified.

51. PINUS PINASTER

1768 P. sylvestris Miller, Gard. Dict. ed. 8 (not Linnaeus).

1789 P. pinaster Aiton, Hort. Kew. iii. 367.

1798 P. laricio Savi, Fl. Pisa. ii. 353 (not Poiret).

1804 P. maritima Poiret in Lamarck, Encycl. Meth. v. 337 (not Lambert).

1826 P. escarena Risso, Hist. Nat. ii. 340.

1835 P. Lemoniana Bentham in Trans. Hort. Soc. Lond. ser. 2, i. 512, t.

1845 P. Hamiltonii Tenore, Cat. Ort. Nap. 90.

Spring-shoots sometimes multinodal. Bark-formation early. Leaves binate, from 10 to 20 cm. long, stout and rigid; resin-ducts medial, hypoderm multiform, the inner cells gradually larger, remarkably large in the angles of the leaf. Conelets minutely mucronate. Cones from 9 to 18 cm.

long, nearly sessile, ovate-conic, symmetrical or subsymmetrical, persistent, sometimes serotinous; apophyses l.u.s.trous nut-brown or rufous brown, conspicuously pyramidal, the umbo salient and pungent.

A maritime tree corresponding nearly, in its range, with the preceding species, but more hardy in cooler climates. It grows from Portugal to Greece, and from Algeria to Dalmatia, but its area has been much extended by cultivation. Under favorable conditions it attains large dimensions, but its exploitation for resin and turpentine tends to diminish its size and disfigure its habit (Mathieu, Fl. Forest, ed. 4, 611). Its rapid growth, strong root-system, and its ability to thrive on poor sandy soil, have led to the employment of this species for the forestation of sand-dunes in France.

The tree can be recognized by its long stout leaves and persistent brown cones. Its leaf-section is peculiar in the remarkable size of the inner cells of the hypoderm, especially in the angles of the leaf.

Plate x.x.xII.

Figs. 275, 276, Cones. Fig. 277, Magnified leaf-section. Fig. 278, Magnified dermal tissues in the angle of the leaf.

[Ill.u.s.tration: PLATE x.x.xII. P. PINASTER (275-278), HALEPENSIS (279-283)]

52. PINUS VIRGINIANA

1768 P. virginiana Miller, Gard. Dict. ed. 8.

1789 P. inops Aiton, Hort. Kew. iii. 367.

Spring-shoots multinodal, pruinose; branchlets pliant and tough.

Bark-formation slow, the cortex not rifted for some years. Leaves binate, from 4 to 8 cm. long; resin-ducts medial, or with an occasional internal duct; hypoderm biform. Conelets with long tapering sharp scales. Cones from 4 to 6 cm. long, ovate or oblong-ovate, symmetrical, persistent, dehiscent at maturity; apophyses l.u.s.trous nut-brown, somewhat elevated along a transverse keel, the umbo salient, forming a long slender p.r.i.c.kle with a broad base.