PIXUS 



PIN US 



1347 



in their native habitats they usually occupy the less 

 fertile situations, as dry uplands and sandy plains. 

 Some, as P. rigida, Cubensis and Toeda, can be grown 

 both in dry and in swampy ground. Pimis palustris is 

 very unhappily named r . 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. ins ignis, Pinaster, Halepensis 

 and also P. rigida are valuable. 



Pines cannot be transplanted successfully when old 

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

 nursery-grown trees should be used for planting. 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 either in prepared 

 beds or frames or in boxes or pans ; the seeds should be 

 covered only slightly with fine soil, but the larger ones 

 about a quarter of an 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. 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 N. 

 America P. palustris, Strobus and echinata; in the 

 western states P. Lambertiana, monticola and pon- 

 derosa; in Europe P. sylvestris and Laricio; in eastern 

 Asia P. Thunbergi and densiflora, and in the Himalayas 

 P. excelsa. From the resinous secretions of many 

 species, chiefly P. palustris, Ciibensis, Pinaster, Hal- 

 epensis and longifolia, turpentine, tar and pitch are 

 obtained. An essential oil used medicinally is distilled 

 from the Ivs. and young shoots of several species. 

 Edible seeds are produced by some species, in America 

 by P. edtilis and cembroides; in Europe by P. Pinea and 

 Cembra, in E. India by P. Gerardiana. Mats similar 

 to Cocoa mats are manufactured from the Ivs. of P. 

 paliistris and Pine wool for stuffing mattresses is made 

 from Ivs. of European and American species. 



About 75 species are known, distributed through the 

 northern hemisphere from the arctic circle to Mexico 

 and the West Indies, N. Africa and the Malayan Archi- 

 pelago; in the tropical and subtropical regions they are 

 confined to the mountains. Resinous trees, rarely 

 shrubs; winter-buds covered with imbricate scales: Ivs. 

 of 2 kinds; the primary Ivs. are spirally arranged and 

 as they appear on young seedling plants and occasion- 

 ally on shoots from the old wood, are green and 

 subulate, but commonly they are reduced to small 

 scarious bracts bearing in their axils the acicular, semi- 

 terete or triangular secondary Ivs. borne on an unde- 

 veloped branch let in clusters from 2-5, rarely reduced 

 to 1, surrounded at the base by sheaths of 8-12 bud- 

 scales: fls. monoecious; the staminate ones axillary, 

 clustered at the base of the young shoots, catkin-like, 

 yellow, orange or scarlet, composed of spirally arranged 

 numerous 2-celled anthers with the connective enlarged 

 and scale-like at the apex (Fig. 1813); pistillate lateral 

 or subterminal, greenish or purplish, consisting of 

 numerous spirally arranged scales each in the axil 

 of a small bract and bearing 2 ovules inside near the 

 base (Fig. 1814) : cone subglobose to cylindric, with 

 woody scales closely appressed before maturity and 

 tightly enclosing the seeds, which are usually furnished 

 with a long thin wing, but in some species are wing- 

 less or short-winged; the apex of the scales is usually 

 more or less thickened and the exposed part, which is 

 usually rhombic in outline and termed apophysis, is 

 often protracted into prominent bosses or knobs; the 

 apophysis is terminated by the umbo, usually differing 

 in color and ending mostly in a spine or prickle. In P. 

 Strobus and the allied species the apophysis is flat and 

 thin, and bears the spineless umbo at the upper end, 

 while in most other Pines the apophysis is thickened 

 and transversally keeled and bears the umbo in the 

 middle. These differences belong to the most impor- 

 tant characters in the grouping of the species : other val- 

 uable characters are furnished by the structure of the 

 Ivs., which contain either 1 or 2 fibre-vascular bundles 



and usually 2 or more resin-ducts, being either pe- 

 ripheral, i. e., situated beneath the epidermis; or par- 

 enchymatous, i. e., enclosed by the tissue of the leaf; 

 or internal, i. e., near the fibro-vascular bundles; 

 strengthening cells, i. e., cells with thickened walls, are 



1815. Pinus Strobus. 



Leaf with a single fibro-vascular bundle (a), usually 

 two peripheral resin-ducts (6) ; strengthening cells (c) 

 only beneath the epidermis ; stomata (d) only on the 

 two inner sides. 



mostly present beneath the epidermis and often sur- 

 round the resin-ducts, sometimes also along the fibro- 

 vascular bundles. (See Figs. 1815-1818). Thenumberof 

 the fibro-vascular bundles and the position of the resin- 

 ducts can be readily seen with a common magnifying 

 glass in thin cross-sections made with a sharp razor 

 from the middle of the leaf and placed on a glass-plate. 

 In the following enumeration the species are grouped 

 according to Mayr's classification, with a few slight 

 changes; his names of his sections, however, are 

 omitted, since they are mostly not well chosen, and the 

 sectional and subsectional names of Engelmann sub- 

 stituted as far as his groups could be brought in accord- 

 ance with those of Mayr. To facilitate the determination 

 of the cultivated species a key is given to determine 

 plants without cones. Good illustrations are found in 

 Sargent, Silva of N. America, vol. 11 ; Lambert, Descrip- 

 tion of the genus Pinus ; Lawson, Pinetum Britannicum ; 

 Forbes, Pinetum Woburnense; Antoine, Die Coniferen. 

 For the horticultural vars. see Beissner, Nadelholz- 



- -C 



1816. Pinus Coulteri. 



Leaf with two fibro-vascular bundles (a); several 

 parenchymatous resin-ducts (b) ; strengthening cells (c) 

 around the resin-ducts, several layers bMpath tLe epi- 

 dermis and along the inner and the outer side of the 

 fibro-vascular bundles; stomata (d) all around. 



kunde and the new edition by A. H. Kent of Veitch's 

 Manual of the Coniferae. Among other important works 

 may be mentioned E. A. Carriere'%Trait6 General des 

 Coniferes, 2d edition, 1867; Heinrich Mayr's Die 

 Waldungen von Nordamerika, 1890; Englerand PrAtl's 

 Die Natiirlichen Pflanzenfamilien II Teil, 1. Abteilung, 

 pages 70-74 (Leiferung 3 and 4); G. Engelmann's 

 vision of the Genus Pinus, in Transactions 01 

 Academy of Science of St. Louis published in 

 Maxwell T. Masters in Journal of the Linnean Soci 

 volumes 22 (1886) and 27 (1889); Conifer Conferenc 

 Journal Royal Horticultural Society, volume 14 ( 1[ 



For a fuller account of the relative value of speciep of 

 Pinus and their culture, see Pine. 



