Minnesota Plant Life. ^^y 



come blended, conditions might arise, when, by the deep groov- 

 ing of the pistil, the carpels would again be separated and such 

 a secondary separation wouy-J. mark a higher type than the orig- 

 inal blended condition. It is sometimes difficult to tell whether 

 a separation of the carpels is primitive or secondary. In the 

 region of the stamens the separate leaves indicate a primitive 

 type, while the blending of the stamens into a tube, as in the 

 mallows, is regarded as an improvement, and consequently indi- 

 cates a higher type. Likewise the blending of the parts of the 

 calyx into a tube is regarded as a modification of that original 

 condition in which the calyx leaves were separate. 



Not only may parts of the same group blend with each other, 

 but they may also blend with the group next to them. Thus the 

 production, in orchid flowers, of stamens apparently springing 

 from the surface of the pistil is regarded as evidence of the 

 blending together into one body of what were originally sepa- 

 rate stamens and pistils. For this reason the orchid flower, in 

 which such a condition has arisen, is regarded as higher in type 

 than the lily flower, for in the latter the blending of stamens 

 and pistil has not been effected. A great many such blend- 

 ings exist. Sometimes the stamens are produced upon the 

 petals or upon the calyx leaves. Sometimes both the petals 

 and stamens seem to arise from the calyx, indicating a fusion 

 into one body of all three regions of the flower — a condition 

 evidently remote from the primitive type, and, therefore, indica- 

 tive of higher rank. Especially is the blending of the calyx 

 with the surface of the pistil regarded as an improvement over 

 the condition in which these two areas are quite distinct. Apple 

 flowers, for example, develop petals and stamens upon the 

 calyx and the latter is blended with the surface of the carpels, 

 giving an additional protective layer to the seeds and permit- 

 ting the important function of assisting in seed-distribution to 

 be borne by a part of the flower below the essential organs. 

 In willow-herbs, too, or fireweeds, the calyx is blended with 

 the pistil, and when the capsule is mature it consists of two 

 protective layers around the seeds instead of one. All these 

 blendings of parts indicate higher rank. 



Another way in which flowers become modified from prim- 

 itive forms is by the development of differences between the 



