DEVELOPMENT OF PLANTS 



343 



(c) The Principal Genera of Pinales. — The more important 

 genera of Pinales may be distinguished as follows: Pinns or 

 pine, leaves long and needle-like, borne in fascicles on short stems 

 that are quite concealed by papery sheathing scales (Fig. 251, 1). 

 Larix or larch, short needle-like leaves clustered in tufts on short 

 lateral branches. This is the only northern member of the order 

 with deciduous leaves. Picca or spruce, leaves angled or four- 

 sided, radiating from all sides of stem, petioles remaining on 

 branchlet after leaves fall, thus causing the rough appearance of 

 the branchlets (Fig. 260, 9). Tsuga or hemlock, leaves flat in 



Fig. 260. Common examples of the Pinales: 5, Thuja or arbor vitae. 

 6, Strobilus of Chamaecyparis or southern white cedar. 7, strobilus of 

 J uni penis or red cedar with fleshy scales fused into a berry-like fruit. 8, 

 branch of Taxus or yew. The seeds are produced singly in the axil of a 

 leaf on short lateral branches and nearly enveloped by a thick fleshy cup 

 that becomes bright red. 9, Picca or spruce. 



