214 APPLIED BIOLOGY 



as Gymnosperms (meaning naked seeds). The most familiar 

 examples are the conifers (a word meaning cone-bearers), 

 including pine, hemlock, larch, spruce, and similar trees. 

 Other gymnosperms are the cycads seen in greenhouses, and 

 the Japanese gingko tree in American parks. 



The Angiosperms and Gymnosperms together constitute 

 the great division of plants known as Spermaphytes (meaning 

 seed-plants). Seed-plants are by some botanists called 

 Phanerogams (meaning visible organs of reproduction, i.e., 

 flowers). The term seed-plants is better than flowering 

 plants, because gymnosperms do not have true flowers ; and, 

 strictly speaking, flowering plants would include only an- 

 giosperms. The following table shows the relations of these 

 groups of plants mentioned above. 



Groups of Seed-plants 

 Spermaphytes Gymnosperms 



Phanerogams Angiosperms Monocotyledons 



Dicotyledons 



210. Gymnosperm Reproductive Organs. Only these 

 organs of gymnosperms are selected for special mention, be- 

 cause in stem, roots, and leaves there is great similarity to 

 angiosperms already studied. The stems of the conifers 

 have the general plan of the dicotyledons, with secondary 

 growth causing annual enlargement of diameter (Fig. 46). 

 Most conifers have needle-like leaves adapted to severe 

 conditions of weather, cycads have leaves suggesting those of 

 palms (which are monocotyledons), the gingko tree has 

 broad leaves, and the arbor-vitae has scale-like leaves. Also, 

 most of the conifers are evergreens, that is, their leaves live 

 several years and do not all fall at a certain season ; but the 

 common larch or tamarack is a conifer that sheds its leaves 

 annually like most dicotyledon trees, and there are many 

 evergreen shrubs and trees among angiosperms. In short, 

 there is no important characteristic of leaves in gymnosperms 



