CHAPTER IX 

 THE CR(3WF()()T FAMILY 



101. General features. In .severul respects the crowfoot 

 family is the Ix'st one with whicli to begin our study of plant 

 groups. It forms an especially serviceable standard of com- 

 parison l)ecause its members, as we shall see, are remarkably 

 simple in their plan of structure — at least for seed-plants — 

 and at the same time the various species tUsplay a wide range 

 of variety in detail. Moreover, it was his careful study of 

 this family which led the j'ounger .Jussieu to an understanding 

 of those fundamental principles of classification which he 

 applied so l)rilliantly in founding the natural SA'stcm. To us 

 it will present problems which once solved will simplify and 

 illuminate all our future study. 



Of the plants already examined the following, as we have 

 seen, are of this family: marsh-marigold (Caltha palustris, 

 page 198j, tall liuttercup (Ranunculus acris, page 210), 

 ditch crowfoot (R. sceleratus, ])age 216), wind-flower (Ane- 

 mone nemerosa, page 20.5), and monkshood (Aeonitum 

 Najx-Uus, i)age 191). The famih' is made up of al)out 700 

 species in about oO gen(>ra. From the few exami)les al)Ove 

 given and a study of those shown in Figs. 282-297, we may 

 gain, however, a fair idea of the range of peculiarities exhil> 

 ited bj' the family as a whole. At first sight it may seem 

 scarcely possilile to find among plants which differ so nuich 

 one from another any i)eculiarit>- or set of peculiarities 

 common to all and yet not possessed by other seed-jjlants. 

 Examination ^\ill show us, however, that as a group they 

 may be distinguislied at least by fh(> lack of complicating 

 fealrires which other families show, and we shall find furtlier- 

 morc a few pusitive |)eculiari( ies which are more or less 

 characteristic. 



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