14 



THE PHYLOGENETIC METHOD IN TAXONOMY. 



in 1920. These at once revealed a striking similarity between the traditional treatment 

 of the species as exemplified by Linnaeus, Bentham, Gray, and others and the ecological 

 treatment based upon the fullest recognition of evolutionary processes. This was not 

 merely evident in the total number of species, but with rare exceptions the numbers 

 were also in close agreement for the 91 genera considered. While the evidence can 

 not, in the nature of the case, be regarded as conclusive, it is strongly suggestive of 

 the fact that the traditional concept and the ecological concept of the species are based 

 upon the same phylogenetic unit and are essentially identical. 



The scientific basis of species. — The basic essentials of the evolutionary treatment of 

 species are a fixed species concept and their determination primarily in the field. In 

 spite of occasional exceptions, the traditional species concept, crystallized by Linnaeus, 



Table 2. — Number of species in representative genera. 



Rydberg, 

 1917. 



Clements, 

 1913. 



Coulter, 

 1885. 



Coulter 



and 



Nelson, 



1909. 



Rydberg, 

 1917. 



Clements, 

 1913. 



Ranunculus . . 

 Aquilegia .... 

 Delphinium. . 

 Aconitum. . . . 



Draba 



Arabis 



Lepidium .... 

 Erysimum . . . 

 Lesquerella. . . 



Roripa 



Viola 



Geranium .... 



Arenaria 



Clay tonia 



Polygonum . . . 

 Eriogonum . . . . 

 Chenopodium . 



Atriplex 



Salix 



Euphorbia . . . . 

 Dodecatheon . . 

 Polemonium. . . 



Phlox 



Gilia 



Gentiana 



Frasera 



Phacelia 



Lithospermum 

 Krynitzkia . . . . 



Mertensia 



Lappula 



Pentstemon . . . 



Mimulus 



Castilleia 



Pedicularis. . . . 



Monarda 



Rosa 



Potentilla 



Fragaria 



Geum 



Lupinus 



Astragalus . . . . 



Aragalus 



Vicia 



Lathyrus 



Trifolium 



Saxifraga 



Heuchera 



19 

 36 

 11 

 50 

 50 

 29 

 16 

 21 

 18 

 28 

 19 

 36 

 22 

 38 

 122 

 23 

 37 

 76 

 30 



15 

 80 

 196 

 34 

 9 

 21 

 47 



Ribes 



Quercus 



Epilobium. . . . 



Oenothera 



Mentzelia 



Opuntia 



Ligusticum. ... 

 Lomatium .... 



Galium 



Valeriana 



Gutierrezia 



Grindelia 



Chrysopsis 



Haplopappus. . . 

 Chrysothamnus 



Solidago 



Aster 



Townsendia. . . . 



Erigeron 



Antennaria 



Helianthus 



Hymenopappus. 



Actinella 



-Artemisia 



Arnica 



Senecio 



Carduus 



Crepis 



Agoseris 



Tradescantia . . . 



Allium 



Zygadenus 



Sisyrinchium. . . 



Juncus 



Carex 



Agrostis 



Aristida 



.Stipa 



Poa 



Festuca 



Bromus 



Agropyrum .... 

 Elymus 



Total . . . . 

 Average No. of 

 species per 

 genus 



17 



12 



14 



40 



13 



31 



7 



9 



3 



7 



23 



7 



21 



12 



7 



4 



1 



13 



4 



2 



17 



87 



5 



3 



29 

 18 

 13 

 11 

 17 

 27 

 61 

 42 

 34 

 139 

 21 

 102 

 43 

 15 

 11 

 28 

 72 

 40 

 114 

 58 

 20 

 33 

 5 

 35 

 11 

 11 

 37 

 162 

 20 

 7 

 21 

 67 

 26 

 24 

 23 



2 



1 



2 



1 



16 



9 



11 



31 



11 



19 



7 



; 

 1 



6 

 17 



5 

 26 



