CHAPTER IV — SPERMATOPHYTES 



Introductory. — The Spermatophytes (seed plants) include the most 

 highly organized plants, and are distinguished from the lower groups by 

 the production of seeds. Once they were called Phanerogams, a name 

 contrasted with Cryptogams, which included all the lower groups. 

 Phanerogam means " sexual reproduction evident," and cryptogam 

 means " sexual reproduction concealed." This distinction was based 

 upon the belief that stamens and pistils are sexual organs, and that no 

 such organs are evident in the lower groups. In fact, the sexual organs 

 are very evident in the groups included under cr3fptogams ; while they 

 are very obscure in the so-called phanerogams. 



The seed plants were also generally called flowering plants, but the 

 flower is not a structure that defines the group. There are two possible 

 definitions of a flower. A very common one is that it is essentially a 

 group of sporophylls (stamens and carpels); but this definition includes 

 the strobilus, a structure well represented among pteridophytes. An- 

 other definition of a flower is that it is a structure in which a perianth 

 (sepals and petals) is associated with the group of sporophylls; but this 

 definition excludes many seed plants, and especially all the gymno- 

 sperms. The limit of the flower, therefore, is either more extensive 

 than seed plants or less extensive; and since the structure does not fit 

 the group, the name flowering plants has been abandoned. The seed 

 is a structure that seems to agree exactly with the boundary of the group, 

 and therefore the name seed plants (spermatophytes) seems to be the 

 most appropriate. 



The two groups of spermatophytes are Gymnosperms and Angio- 

 s perms, the names expressing the conspicuous difference ; for in gymno- 

 sperms the seeds are exposed, and in angiosperms they are enclosed in a 

 case. This difference is very far from expressing the full contrast be- 

 tween these two groups, but the characters will be developed as the groups 

 are described. It is suflficient to state here that the gymnosperms are 

 very ancient and form a comparatively small part of the present seed 

 plant vegetation; while the angiosperms are comparatively modern 

 and include the great bulk of the present seed plant vegetation. 



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