420 A TEXTBOOK OF GENERAL BOTANY 
ORDER CONIFERALES 
The conifers are woody plants ranging in size from shrubs 
to the giant Sequoia of California. Many of them contain 
numerous resin canals (Fig. 121). 
Leaves. The leaves are xerophytic (Fig. 475), are usually 
small, and in many species are needlelike or scalelike. In a few 






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Fia.475. Cross section of leaf of pine (Pinus insularis) 
genera the lamina is rather broad (Fig. 476). The leaves usually 
remain on the plant for several years, being deciduous in only 
three genera. 
Stem structure. The arrangement of the vascular bundles and 
of the secondary thickening of the conifers is very similar to 
that of dicotyledonous angiosperms. There is a small pith sur- 
rounded by a wide woody cylinder. The structure of the wood 
differs from that of dicotyledons in that it contains only tra- 
cheids and wood parenchyma and lacks vessels and wood fibers 
(Fig. 130). The tracheids serve both for water conduction and 
as strengthening elements. Owing to the absence of vessels and 
