450 ORIGIN OF CULTIVATED PLANTS. 



fruits agreeable to the taste, or textile, tinctorial, oil- 

 producing plants, or yielding stimulating drinks by 

 infusion or fermentation. There are among these only 

 two green vegetables, and no fodder. The orders whicli 

 predominate are the Cruciferse, Leguminosse, and Gra- 

 minaceae. 



The number of annuals is twenty-two out of the 

 forty-four, or lifty per cent. Out of five American species 

 marked D, two are annuals. In the category A, there 

 are two biennials, and D has none. Among all the 

 Phanerogams the annuals are not more than lifty per 

 cent., and the biennials one or at most two per cent. It 

 is clear that at the beginning of civilization plants which 

 yield an immediate return are most prized. They offer, 

 moreover, this advantage, that their cultivation is easily 

 diffused or increased, either because of the abundance of 

 seed, or the same species may be grown in summer in the 

 north, and in winter or all the year round in the tropics. 

 • Herbaceous perennial plants are rare in categories A 

 and D. They are only from two to four per cent., 

 unless we include Brassica oleracea, and the variety of 

 flax which is usually perennial {L. angiistifolium), culti- 

 vated by the Swiss lake-dwellers. In nature herbaceous 

 perennials constitute about forty per cent, of tlic Phane- 

 rogams.-^ 



A and D include twenty ligneous species out of forty- 

 nine, that is about forty-one per cent. They are in the 

 proportion of fort3^-three per cent, of the Phanerogams. 



Thus the earliest husbandmen employed chiefly 

 annuals or biennials, rather fewer woody species, and far 

 fewer herbaceous perennials. These differences are due 

 to the relative facility of cultivation, and the proportion 

 of the evidently useful species in each division. 



The species of the old world marked B have been in 

 cultivation for more than two thousand years, but per- 

 haps some of them belong to category A. The American 



^ The proportions which I give for the Phanerogams collectively ai-c 

 based upon an approximative calculation, made with the aid of the first 

 two hundred pages of Steudel's Nomenclator. They are justified by 

 the comparison with several floras. 



