2] THE VARIOUS GROUPS OF PLANTS 65 



of lateral shoots or branches and their separate growth on segregation 

 from, or death of, the parent. 



Among the Gymnosperms, the usually stocky and unbranched 

 Cycads, with their palm-like crown of huge compound leaves, are 

 chiefly characteristic of the drier areas of the tropics and subtropics, 

 as are the much-branched, bushy Ephedras, though their broad- 

 leafed relatives, the Gnetums, favour moist tropical habitats. Far 

 more numerous, important, and widespread, however, are the 

 Conifers, different members of which occupy almost the complete 

 range of land habitats from swamps to dry sands. They dominate 

 vast areas of temperate and boreal forests, many of which they 

 virtually compose, and constitute the northern limit of arborescent 

 growth practically around the top of the globe, as well as, often, 



B 



{See p. 67.) 



