136 
THE DICTIONARY OF GARDENING, 
PINNATIFID. Divided into lobes from the margin 
Fie. 160. PINNATIFID LEAF. 
nearly to the axis. A Pinnatifid leaf is shown at 
Fig. 160. 
PINNATILOBED. 
to an uncertain depth. 
PINNATIPARTITE. When the lobes pass 
beyond the middle and the parenchyma is not inter- 
rupted. ; 
PINNATISECT. When the lobes are divided down 
to the midrib, and the parenchyma is interrupted. 
When the leaves are divided 
oy The secondary division of a pinnate 
= PINUS (the old Latin name used by Virgil, &c.; 
probably derived from pia, picis, pitch; alluding to the 
resinous exudations), Deal-tree; Pine-tree. ORD. Ooni- 
fere. 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 monœcious. 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. 
Fic. 161. TRANSVERSE SECTION OF LEAF OF PINUS EXCELSA. 
1, 1, Strengthening Cells; 2, 2, Ducts, surrounded by Strengthening 
Cells; 3, Wavy wy aay 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 
Pinus—continued. 
the fruit-scale, or, rather, to speak more correctly, 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 SYLVESTRIS. 
4.12; aro ia ag, oe 2, 2, Ducts, surrounded by Strengthen- 
ing. Cells; 3, Wavy Chlorophyll-bearing Cells that fill the 
entire space between the Strengthening 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, t.e. in the cellular tissue of the leaf (see 
Fig. 163. TRANSVERSE SECTION OF LEAF OF PINUS COULTERI. 
1, 1, 1, Strengthening Cells ;* 2, 2, Internal Ducts, surrounded by 
Strengthening Cells ; Chlorophyll-bearing Cells that fill 
the entire space betw the Strengthening Cells and the 
Bundle Sheath; 4, Bundle Sheath; 5, 5, Position of Fibro- 
vascular Bundles; 6, 6, 6, Stomata. 
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- 
Borve ooa 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 Loudon's Arboretum et Fruticetum 
Britannicum,” Carriére’s “ Traité Général des Conifères,“ 
* 
