SPERMATOPHYTA 421 
wood fibers the wood of the conifers is much more primitive 
than that of the flowering plants. The xerophytic structure of 
the leaves is connected with the primitive nature of the wood 
and the large size 




of the plants, as tra- ‘ “a 
cheids are not as Rah : 

well fitted for con- MA i ! WW 
ducting large quan- 4 
tities of water as are 
vessels. 
Sporangia. ‘The 
microsporangia are 
small and are borne 
in small cones. In 
the majority of gen- 
era the megaspo- 
rangia are also in 
distinct cones, and 
the seed when ripe 
is dry. In some gen- 
era the cone is so 
greatly reduced as 
not to have the ap- 
pearance of a cone 
and produces only 
a single ovule, and 
in this case the seed 
is more or less sur- 
rounded by a fleshy 
covering. 
merine, ‘The pine 
(Fig. 478) is such 
a widely distributed, well-known, and typical conifer that it may 
be taken as a good example of the order known as Conzferales. 
Vegetative structure. The crown has a conical form, owing to 
the fact that both the central stem and the branches have an 

yy f 2 | a 

Fig. 476. A gathis alba, the source of Manila copal 
Lower left, female cone; lower right, small branch 
with male cones (x 3) 

