14 INTRODUCTION. 



real permanence is much longer. Specific and 

 generic Lives have not yet been calculated. 



6. Therefore many of our actual or newly 

 described Genera and Species, may be of re- 

 cent origine, and all may have once sprung at 

 the last rinovation or cataclysm of this Globe, 

 from a lesser number of original types, perhaps 

 found in the fossil plants of our Earth, which are 

 far from being all known as yet, and whose 

 seeds were preserved in mountains, earth, mud 

 or water tiil the catastrophe was over, 



7. It is even possible to ascertain the relative 

 ages and affinities of actual species and Genera, 

 sometimes their very parents or connections in 

 the Genus or the tribe. Those we call hybrids 

 are not always such, they may arise from other 

 deviations; but artificial hybrids are evidently 

 such. All these deviations are still less perma- 

 nent. 



8. As a general rule the real Genera (not the 

 false ones of blending Botanists) of single or 

 few species are the newest in order of time, and 

 the most prolific the oldest in the Series. The 

 same for tribes perhaps. False Genera like Eri- 

 ca^ Carex, Aster, Allium, Lichen, Euphorbia, 

 Mimosa, Geranium ^c. comprizing a crowd 

 of generic distinctions, are as many collections 

 of related Genera, springing from very early 

 sources or types of forms. Extensive natural 

 Genera prolific in Sp. like Rosa, Iris, Quercus, 

 Salix, Oxalis. Malva, Vitis, Lactuca &.c. had 

 also a very old or primitive source. Species 

 prolific in individuals and varieties are always 

 the oldest, and rare Species probably the newest 

 of all, unless they are fragments of extinct 

 groups. 



Such exposition of my principles, and expla- 



