434 LSSSOIfS WITH PLANTS 



was the first to clearly outline them (in 1789), 

 and to arrange the known genera in their proper 

 families. From this time, the family, rather than 

 the species, became the unit in the natural sys- 

 tems of classification. 



560. There are two methods or schemes of ar- 

 ranging the families of plants, of which, among 

 the flowering plants, there ai'e over two hundred. 

 One method conceives of an ideal type of plant, 

 and places that family first which most nearly 

 satisfies this ideal. De CandoUe conceived the idea] 

 or pattern flower to be one with all the parts 

 present, free and distinct. The crowfoot family, or 

 Eanunculace^, contains such plants as its types, 

 and this family was placed first in the classifica- 

 tion. Our familiar systematic botanies are arranged 

 upon the De CandoUean plan, or modifications of it. 



561. The other method tries to make a classifi- 

 cation which shall represent the course of evolu- 

 tion of the vegetable creation. It places first those* 

 plants which are simplest and most generalized in 

 structure, or which we have reason to believe ap- 

 peared first in time. These systems begiu with 

 the flowerless plants ; and they generally end with 

 the composites. 



561a. The De CandoUean sequence of families is the most famil- 

 iar system, particularly in English-speaking countries. It is essen- 

 tially the method of Bentham and Hooker's great "Genwra Planta- 



