136 



THE DICTIONARY OF GARDENING, 



PINNATIFID. Divided into lobes from the margin 



Fio. 160. PINNATIFID LEAF 



nearly to the axis. A Pinnatifid leaf is shown at 

 Fig. 160. 



PINNATILOBED. When the leaves are divided 

 to an uncertain depth. 



PINNATIPABTITE. When the lobes pass 

 beyond the middle and the parenchyma is not inter- 

 rupted. 



FINNATISECT. When the lobes are divided down 

 to the midrib, and the parenchyma is interrupted. 



PIlTirUIiE. The secondary division of a pinnate 

 leaf. 



PINUS (the old Latin name used by Virgil, &c. ; 

 probably derived from pix, picis, pitch; alluding to the 

 resinous exudations). Deal-tree; Pine-tree. ORD. Coni- 

 ferae. A genus comprising about seventy species of 

 mostly hardy, evergreen trees, rarely shrubs, broadly 

 dispersed over the extra-tropical regions of the Northern 

 hemisphere; a few being found between the tropics 

 in Eastern Asia, the West Indies, and Central America. 

 Flowers monoecious. Leaves dimorphous; primary ones 

 small, scale-like, scarious or hyaline, marcescent, spirally 

 many- seriate ; secondary ones conspicuous, two to five in 

 a whorl in the axils of the small scales, acicular, rather 

 long, sometimes very long. Cones ovoid, conical, or 

 oblong, usually sessile, solitary or fasciculate, slightly 

 erect, horizontal, or reflexed, very rarely less than lin., 

 and sometimes more than 1ft., in length. Seeds fur- 

 nished with ample wings, or wingless. 



/ 5 



FIG. 161. TRANSVERSE SECTION OF LEAF OF PINUS EXCELSA. 



1, 1, Strengthening Cells ; 2, 2, Ducts, surrounded by Strengthening 

 Cells ; 3, Wavy Chlorophyll-bearing Cells that fill the entire 

 space between the Strengthening Cells and the Bundle Sheath ; 

 4, Bundle Sheath; 5, Position of Fibro-vascular Bundle; 

 6, 6, Stomata ; 7, Internal Duct. 



In most books, the .species are classified according to 

 the number of leaves in a sheath, but here the arrange- 

 ment adopted is that proposed by the late Dr. Engel- 

 mann, published in the "Transactions of the St. Louis 

 Academy of Science," and reprinted in the " Gardeners' 

 Chronicle" for July 20th, 1880. Dr. Engelmann says: 

 " I find, with Endlicher, the most valuable character in 



Finns continued. 



the fruit-scale, or, rather, to speak more correotly, I 

 find that the form of the fruit-scale in this genus cor- 

 responds with a series of other characters which con- 

 stitute two very natural sections of this genus 



The sub-sections are distinguished by the position of 

 the ducts within the leaf, whether peripheral, i.e., near 



FIG. 162. TRANSVERSE SECTION OF LEAF OF PINUS SYLVESTIUS. 



1, 1, 1, Strengthening Cells ; 2, 2, Ducts, surrounded by Strengthen- 

 ing Cells; 3, Wavy Chlorophyll-bearing Cells that fill the 

 entire space between the Strengthen! n; Cells and the Bundle 

 Sheath ; 4, Bundle Sheath ; 5, 5, Position of Fibro-vascular 

 Bundles; 6, 6, Stomata. 



the epidermis (see 2, 2, Figs. 161 and 162), paren- 

 chymatous, i.e., in the cellular tissue of the leaf (seo 



FIG. 163. TRANSVERSE SECTION OF LEAP OF PINUS COULTERI. 



Internal Ducts, surrounded by 



1, 1, 1, Strengthening Cells ; 



Strengthening Cells ; 3, Chlorophyll-bearing' Cells that fill 

 the entire space between the Strengthening Cells and the 

 Bundle Sheath ; 4, Bundle Sheath ; 5, 5, Position of Fibre- 

 vascular Bundles ; 6, 6, 6, Stoinata. 



2, 2, Fig. 163), or internal, i.e., close to the bundle 

 sheath. Subordinate to this character is the sub- 

 terminal or lateral position of the female ament 

 and the cone. Only after this may the number of 

 leaves in a sheath be taken into consideration, and 

 perhaps the presence or absence of strengthening 

 cells (see 2, 2, Figs. 161, 162. 163) around the ducts. 

 It will be found that thus not only natural, but, to 

 some extent, even geographical, alliances are best pre- 

 served " Want of space has prevented the cha- 

 racters of the sub-sections from being given ; these will 

 be found fully detailed in the works above-mentioned. 

 For full descriptions, and more information respecting 

 the species than it is possible to give in this work, the 

 reader is referred to London's " Arboretum et Fruticetum 

 Britannicum," Carriere's " Traite General des Coniferes," 



