SPECIES 219 



nature of tlio case is such tliat it i)r()l)al)ly must always remain so. In 

 spite, however, of all these imjierfections, steady and great progress has 

 been and is being made, and this natural system of classification must 

 be regarded as a most useful attemi)t to indicate just such genetic 

 relationships as exist among human beings. 



The divisions and sub-divisions thus established stand as ft>llows: 



Divisions. — Of which there are two, the Cryptogamia and Phanero- 

 gamia, the latter being now often called Spermatophyta, as the pro- 

 duction of seeds is regarded as their most important characteristic. 



Sub-divisions. — Leaving out of consideration the divisions of the 

 Cryptogamia, we find the Phanerogamia divided with two sub-divisions, 

 the Gymnospcrmae and the Angiosperniae, the latter the higher. 



Classes. — Leaving out of account the Gymnospermae, the Angio- 

 spermae are divided into two classes, the Monocotyledons and the 

 Dicotyledons. 



Series. — The Dicotyledons are divided into three series, the Thal- 

 amiflorae, Disciflorae and Calycifiorae. 



Cohorts. — Each of the series named above is divided into a num])er of 

 Cohorts, or orders. Thus the Thalamiflorae have G cohorts, namely, 

 Ranales, Parietalcs, Polygalinae, CaryophylUneae, Guttifcrales, and 

 Mai vales. 



Families. — Each cohort consists of a number of Fatnilics, of which 

 there are about 3{)() among flowering plants, the Ranunculaceae or 

 Buttercup Eamily and the Compositae or Daisy Eamily being exam})les. 



Sub-families and Tribes. — Families, if large or heterogeneous, are 

 often divided into Tribes, or into Sub-families, the latter then divided 

 into Tribes. Thus, the Ranunculaceae contain 5, the Compositae 13 

 tribes. 



Genera. — Families, either directly or through their tribes, are divided 

 into genera, of which the most modern authorities recognize between 

 8()()() and 9(K)() in all the families of flowering ])lants. The genera are 

 very irregularly distributed among the families. Thus, the family 

 Columelliaceae contains but one genus, Coluinellia,\\hi\e the CoDiposiiae 

 is made up of some SOO of them. 



Species. — Genera, either directly or through a number of Sub-genera, 

 are made u]) of species, of which there are })robal)ly not far from 2r)(),()()() 

 now described among flowering plants. These are very irregularly 

 distributed among the genera, many of the latter containing but one 

 species, while others contain hundreds. Solanuui. pi-obablx' tlic largest 

 genus, has been credited with as many as 1200 species. 



