2634 



PINUS 



PINUS 



purpose. For planting rocky slopes P. Banksiana, P. 

 rigida, P. virginiana, and some western species are valu- 

 able; and if dwarf forms are desired P. montana is one 

 of the best, thriving better than any other species in 

 shaded positions and as undergrowth in open woods. 



A great number of the species are hardy North. 

 Among the hardiest are P. Strobus, P. Cembra, P. 

 parviflora, P. Bungeana, P. koraiensis, P. rigida, P. 

 Banksiana, P. Thunbergii, P. resinosa, P. sylvestris and 

 P. montana. The Mexican species and those from 

 southern Asia stand only a few degrees of frost. 



The pines are not very particular as to the soil, and 

 in their native habitats they usually occupy the less 

 fertile situations, as dry uplands and sandy plains. 

 Some, as P. rigida, P. caribsea, and P. Tseda, can be 

 grown both in dry and in swampy ground. P. palustris 

 is very unhappily named, since it almost never grows in 

 swamps. Pines are much used for the afforestation of 

 barren sandy plains and dry rocky mountain slopes. 

 For seaside planting P. rigida and the more tender P. 

 radiata, P. Pinaster, P. halepensis, and P. canariensis 



2961. Pinus echinata. 



Leaf with two fibro-vascular bundles (a) and several medial 

 resin-ducts (ft) ; only one layer of strengthening cells (c) beneath 

 the epidermis; stomata (d) all around. 



are valuable; the last three species are now much 

 planted in California, both for timber and ornament. 



Pines cannot be transplanted as successfully as large 

 plants on account of their long tap-roots, and only 

 younger nursery-grown trees should be used for plant- 

 ing. As they cannot usually be taken up with a good 

 ball of earth, it is well to immerse the roots in a loam 

 puddle immediately after the trees are dug up. 



Pines are propagated by seeds sown in spring in 

 prepared beds or frames, or in boxes or pans; the 

 seeds should be covered slightly with fine soil, but the 

 larger ones about % inch, and the young seedlings 

 shaded and watered when necessary. Varieties and 

 rarer kinds are grafted on their types or allied species, 

 usually by veneer-grafting on potted stock in the green- 

 house in winter, or in spring outdoors by cleft-grafting 

 in the terminal bud (M.D. 1901, p. 15). Cuttings even 

 of the dwarf forms do not root readily; the easiest to 

 root are young shoots with primary foliage, as they 

 sometimes appear on older branches or on the trunk. 



The pines belong to the most important timber trees 

 in their native countries; these are, in eastern North 

 America, P. palustris, P. Strobus, and P. echinata; 

 in the western states, P. Lambertiana, P. monticola, and 

 P. ponderosa; in Europe, P. sylvestris and P. nigra; in 

 eastern Asia, P. Thunbergii and P. densiflora, and in 

 the Himalayas, P. excelsa. From the resinous secretions 

 of many species, chiefly P. palustris, P. caribxa, P. 

 Pinaster, P. halepensis, and P. longifolia, turpentine, 

 tar, and pitch are obtained. An essential oil used 

 medicinally is distilled from the leaves and young 

 shoots of several species. Edible seeds are produced by 

 some species, in America by P. edulis and P. cem- 

 broides; in Europe by P. Pinea and P. Cembra; in East 

 India by P. Gerardiana. Mats similar to cocoa mats 

 are manufactured from the leaves of P. palustris, and 

 pine wool for stuffing mattresses is made from leaves of 

 European and American species. 



For another account of the relative value of species 

 of Pinus and their culture, see Pine. 



NO. I. KEY TO THE SPECIES WITH THE CONES. 



I. SOFT PINES ( Haploxylon). 



Wood soft, close-grained, light-colored, the sap-wood 

 thin and nearly white: sheaths of the If .-clusters deciduous; 

 Ivs. with 1 fibro-vascular bundle. 

 A. Umbo of scales terminal. 



B. Seeds wingless or with rudimentary 



wing. 

 c. Margin of Ivs. serrulate. 



D. Branchlets hairy: cones inde- 



hiscent. 

 E. Cones ovate: branchlets 



brownish tomentose 1. Cembra 



EE. Cones cylindric-conical: 



branchlets pubescent 2. koraiensis 



DD. Branchlets glabrous: cones de- 

 hiscent, cylindric-conical. ... 3. Armandi 

 cc. Margin of Ivs. entire: cones dehis- 

 cent: Ivs. stout, 1 Yi-3 in. long. . 4. flexilis 

 BB. Seeds winged, with long wing, short 



in No. 5. 

 c. Cones less than 10 in. long. 



D. Scales of cone with convex 



thickening. 



E. Length of cone about 2 in., 

 shape ovate: branchlets 

 pubescent: Ivs. %-!}/% in. 



long 5. parviflora 



EE. Length of cone 8^-10 in., 

 shape cylindric: branchlets 

 glabrous. 



F. Lvs. 3-4 in. long, stiff. . . 6. Peuce 

 FF. Lvs. 68 in. long, drooping 7. excelsa 

 DD. Scales of cone uniformly thin. 

 E. Branchlets glabrous: Ivs. 



thin, soft 8. Strobus 



EE. Branchlets at first pubes- 

 cent: Ivs. stiff 9. monticola 



