44 GENUS PINUS 



An alpine species growing often at the timber-limit. It is found in two distinct stations in Califor- 

 nia, on the northern Coast Range and on the southern Sierras. It is not often cultivated, but young 

 plants may be seen in the Arnold Arboretum and in the Royal Gardens at Kew. 

 Plate XV. 



Fig. 147, Cone, seed and enlarged cone-scale. Fig. 148, Leaf-fascicle. Fig. 149, Magnified 

 leaf-section. Fig. 150, A branch with persistent leaves. 



19. PINUS ARISTATA 



1862 P. ARISTATA Engelmann in Am. Jour. Sci. ser. 2, xxxiv. 331. 

 1871 P. Balfouriana Watson in King's Rep. v. 331 (not Balfour). 



Spring-shoots glabrous or temporarily pubescent. Leaves from 2 to 4 cm. long, persistent for many 

 years; stomata ventral only; resin-ducts external. Scales of the conelet prolonged into long slender 

 bristles. Cones from 4 to 9 cm. long, subcylindrical or tapering to a rounded apex, short-peduncu- 

 late; apophyses terracotta or purple-brown, tumid, the long bristles of the umbo often partly or 

 wholly broken away; seeds with a long articulate wing. 



A bushy tree, similar in foliage to the preceding species, growing at the timber-limit from Colorado 

 through Utah, central and southern Nevada and northern Arizona into southeastern California, but 

 separated from the nearest station of P. Balfouriana by an arid treeless desert. Engelmann (in 

 Brewer and Watson, Bot. Calif, ii. 125) considered it to be a variety of P. Balfouriana. 

 Plate XV. 



Fig. 143, Cone. Fig. 144, Seed and enlarged cone-scale. Fig. 145, Leaf-fascicle and mag- 

 nified leaf-section. Fig. 146, Conelet. 



DIPLOXYLON 



Bases of the bracts subtending leaf -fascicles decurrent. Leaves serrulate; fibro-vascular bundle 

 double; stomata dorsal and ventral. Cones with a dorsal umbo, the phyllotaxis complex. Wood 

 hard, with dark resinous bands, the annual rings clearly defined. 



In this section there are a few species combining the essential characters of Diploxylon with 

 important characters of Haploxylon. A subsection, Parapinaster, is established for these excep- 

 tional species. 



c. Parapinaster. . . .Species with the fascicle-sheath or seed-wing of Haploxylon. 



d. Pinaster Sheath persistent, seed-wing articulate, effective. 



Parapinaster 



Sheath of the leaf -fascicle deciduous VII. . . . Leiophyllae. 



Sheath of the leaf-fascicle persistent. 



Seed-wing of the Strobi VIII. . . Longifoliae. 



Seed-wing of the Gerardianae IX. . . .Pineae. 



Vn. LEIOPHYLLAE 



Sheath of the leaf-fascicles deciduous. 



Leaves short, erect, the fructification triennial 20. leiophylla. 



Leaves long, pendent, the fructification biennial 21. Lumholtzii. 



20. PINUS LEIOPHYLLA 



1831 P. LEIOPHYLLA Schlechtendal and Chamisso in Linnaea, vi. 354. 

 1848 P. CHIHUAHUANA Engel^tiann in Wislizenus, Tour. Mex. 103. 



