GYMiSrOSPERMS 



311 



The seed germinates when there are suitable climatic condi- 

 tions. Its embr3'o swells, bursts the seed coat, sends the root 

 down into the soil and the stem and leaves into the air, and 

 is then known as the pine seedling. It may in time become a 

 new pine tree, which will again bear cones and produce seed. 

 It is worthy of note that in some pines, as the lodgepole pine 

 of the Rocky Mountains, the cones may not shed their seeds 

 for several years, sometimes not until the death of the tree. 



Fig. 258. Gymnosperm cones (coutiuued) 



E, "big tree" {Sequoia Washingtonia) , two thirds natural size; F, common 

 juniper (Juniperus communis), three fourths natural size 



287. The Coniferales. The gymnosperms are subdivided into 

 four living groups : the Coniferales, or cone-bearing gymno- 

 sperms ; the Cycadales, plants which in general form resemble 

 the tree ferns and some of the palms ; the Gnetales, a group 

 containing but three genera, which in form are so unlike one 

 another that beginnmg students of botany would not think 

 of classifying them together; the GHnkgoales, represented by 

 one tree form. By far the largest group in number of genera 

 and species and in number of individuals is the coniferales. 



