148 THE TEACHING BOTANIST 



united carpels and calyx. Nothing could be more thor- 

 oughly disproved, or is more easy to disprove by embryo- 

 logical study than this. Embryology shows that, in the 

 great majority of cases at least, the inferior ovary is 

 simply a receptacle which has grown up into a cup, carry- 

 ing all the other parts upon its top, the carpels coming 

 finally to form simply a roof over the cavity of the 

 ovary (as shown in Fig. 28). This fact at once dis- 

 poses of many of the inconsistencies inseparable from 

 the " calyx-adnate ' theory. Again, where a calyx- or 

 corolla- or perianth-tube is formed, it is usual to consider 

 that this tube consists of united sepals, petals, etc., but 

 it is probable that only the free parts or teeth of the 

 corolla or calyx represent the original distinct petals or 

 sepals, while the tube is a band of leaf tissue that grows 

 up as a ring leaf, bearing the separate leaves on its top ; 

 it is thus a new structure and not the united bases of 

 the old perianth parts. 



There are also some minor errors current, of which 

 the following are most important : First, it is usually 

 supposed that root, stem, and leaf of the higher plant 

 are members of equivalent worth. In fact, this is not 

 the case, for root is in every way much more distinct 

 from stem and leaf than these are from one another. 

 The best division then is into root and shoot, with the 

 latter differentiating into leaf and stem. Another error 

 is, that the higher plant is made up of certain elemental 

 parts called phytomera, each of which is composed of a 



