2 CYCADACE.E. 



classification of plants is based ; but we have to discriminate as 

 best we can between valueless and important taxonomic features, 

 and to accept within legitimate limits the assistance of evidence 

 founded on analogy. To exclude fossil plants from a classification 

 based on living types would be at once thoroughly unscientific and 

 unnatural. Recent botany and the botany of past ages have too 

 often been treated from different standpoints, and the great aim of 

 palaBobotanical study has thus been entirely lost sight of. The 

 more we recognize the fact that plant-life, with its innumerable 

 problems awaiting solution, is not confined within the limits of one 

 age in the history of the earth, the sooner ought we to attain to 

 a natural system of classification. 



The more important characters of the Spermaphyta (Embryopliyta 

 siphonogama) may be thus briefly summarized : 



In the great majority of cases the body of the plant is differ- 

 entiated into root, stem, and leaves. The embryo is formed as 

 the result of fertilization, by means of a pollen-grain tube, of an 

 egg-cell enclosed in a macrospore ; the fertilized egg-cell develops 

 into an embryo, which more or less completely fills up the 

 macrospore and macrosporangiuni. The seed may or may not 

 be enclosed in an ovary. The gametophyte (sexual or oophore 

 generation) is considerably reduced, and the sporophyte (asexual 

 or sporophore generation) has become much more conspicuous than 

 in the Pteridophyta. 



Class GYMNOSPERM.E. 



Seeds naked, not enclosed in an ovary. Fertilization of the 

 egg-cell by means of a pollen-tube. Vegetative structures capable 

 of secondary growth in thickness. 



Order CYCADACE^E. 



Stem rarely branched, leaves large and generally pinnate. In 

 the recent genera flowers always dioscious, and without a perianth. 



The Order Cycadacea, like the Maraitiacea among ferns, affords 

 an instance of a series of plants of which few survive at the 

 present day, but which was abundantly represented in the vege- 



