320 HARSHBERGER— TAXONOMIC CHARTS OF THE 



[April 19 



lacese are grouped together not only because of certain structural 

 characters, but because the plants of these orders show a parasitic 

 habit of life. The Portulacacese, Phytolaccacese, Batidacese, Caryo- 

 phyllaceae, Amaranthaceae, Chenopodiacese and Basellacese form an- 

 other natural group, while the Cornacese, the Araliacese and the 

 Umbelliferse form still another important branch of the dicotyledon- 

 ous family tree. The families that by the agreement of most botan- 

 ists form the order of Rhoedales are Resedacese, Cruciferse, Cap- 

 paridacese, Papaveraceas and Fumariacese, while the families that 

 belong to the Ranal Alliance, and are thus suggestive of the Helo- 

 bial Alliance among monocotyledons, are Ranunculacese, Anonaceae, 

 Magnoliacese, Berberidacege, Calycanthacese, Lauracese, etc. The 

 affinity of the families comprising the order, or alliance, Rosales is 

 also very strong. For the other groups and families, the endeavor 

 has been to associate them together in such a manner that the sys- 

 tem of branching will suggest the character of the affinity, whether 

 close or distant. Thus the families at the base of any branch are 

 considered in the scheme to be more primitive than those at the 

 extremity of the branch. The arrangement of the lateral branches 

 and their proximity to each other is suggestive of close or distant 

 relationship. 



The Gamopetalse, which are undoubtedly the highest of the an- 

 giosperms, naturally group themselves into two main trunks, having 

 both a different phylogenetic origin. The writer has represented 

 these main branches, at the suggestion of Campbell,^ as Isocarpeae 

 and Anisocarpese. The families included as Isocarpese show an 

 ovary that consists of as many carpels as there are petals in the 

 flower, and such families are considered to be more primitive than 

 those of the Anisocarpeae, where the syncarpous ovary consists of 

 a less number of carpels than there are petals to the flowers. A few 

 of the isocarpous plants have almost distinct petals and to some 

 extent connect the Apopetalae and the Gamopetalse. The isocarpous 

 families culminate in the Ericaceae, Primulaceae and Styracaceae. 

 The great majority of the gamopetalous families belong to the aniso- 

 carpous division, the less specialized types with regular tubular or 

 funnel-shaped corollas being the morning glories (Convolvulaceae), 



^ Campbell, D. H., " The Evolution of Plants," p. 213. 



