198 



BOTANY. 



present the only suggestion which it gives of belonging to the 

 leaf series is the fact that the end is divided into three parts, 

 the number of parts in each successive whorl of members of the 

 flower. If w r e cut across the 

 body of this pistil and examine 

 it with a low power we see that 

 there are three chambers or cavi- 

 ties, and at the junction of each 

 the walls suggest to us that this 

 body may have been formed by 

 the infolding 

 of the margins 

 of three leaf- 

 like members, 



the places of contact having 

 then become grown together. 

 We see also that from the incurved 

 margins of each division of the pistil 

 there stand out in the cavity oval 

 bodies. These are the ovules. Now the ovules, we have learned 

 from our study of the gymnosperms, are the sporangia (here the 

 macrosporangia). It is now more evident that this curious 

 body, the pistil, is made up of three leaf-like mem- 

 bers which have fused together, each member being 

 the equivalent of a sporophyll (here the macrosporo- 

 phyll). This must be a fascinating observation, that 

 plants of such widely different groups and of such 

 different grades of complexity should have members 

 formed on the same plan and belonging to the same 

 series of members, devoted to similar functions, and 

 stJmen S oTTnU yet carried out with such great modifications that at 

 antoer^ocuuls nr st we do not see this common meeting ground 



: mar-m. ^hj^ a comparative study brings out so clearly. 

 327. Transformations of the flower of trillium. If anything 

 more were needed to make it clear ihat the parts of the flower 



Fig. 178. 

 Abnormal 

 trillium. The 

 nine parts of 

 the perianth 

 are green, 

 and the outer 

 whorls of 

 stamens are 

 expanded into 

 petal-like mem- 

 bers. 



Fig. .79. 



