344 



BOTANY 



(PL XV). Of the numerous West-coast Conifers, the most important 

 are the Redwood (Sequoia sempervirens), Sugar-pine (Pinus Lam- 

 bertiana), Yellow-pine (P. ponderosa), Incense-cedar (Libocedrus 



FIG. 309. A, Tsuga C'anadensis (X 1). B, seminal scale, with large subtending 

 scale of Pseudotsuga Douglasii (X 1). C, seed of P. Douglasii (X 2). 



decurrens), Giant Arbor- vitae (Thuja plicata), Douglas-fir (Pseu- 

 dotsuga Douglasii), Sitka-spruce (Picea Sitchensis'), and several 

 other species of Spruces and Firs. These are all gigantic trees, 



attaining a height of two 

 hundred to three hundred feet, 

 or even more. 



B 



Order IV. Gnetaceae 



This order includes three 

 genera which differ much from 

 each other, but nevertheless 

 show certain structural resem- 

 blances in the flowers and 

 development of the seed. 

 They differ from the Conife- 

 rse in having the flowers pro- 

 vided with rudimentary floral 



FIG. 3io. .4, Cupressus macrocarpa (x 3). envelopes, and are sometimes 

 B, ovuliferous scale, with young seeds, considered to be intermediate 



n ( 2) - C> J TTr US < ^ inian a(x 2) " in character between the Gym- 

 D, Thuja occtdentahs (X 2). J 



nosperms and Angiosperms. 



The secondary wood contains vessels, in which respect they resemble 

 Angiosperms. Of the three genera, but one, Ephedra (Fig. 311), is 

 found within our territory, several species occurring in our south- 

 western arid regions. Gnetum is a tropical genus, found both in 

 the old and new worlds. Welwitschia is a monotypic form, occur- 

 ring in West Africa. 



The species of Ephedra are shrubs with jointed branches, sug- 

 gesting an Equisetum. The leaves are reduced to dry sheathing 



