154 



Introduction to Botany, 



cavity in the ovary, draw the line near the center, fixing 

 the thickness of the central partition wall, as in the right 

 half of diagram L, and then continue this line to form the 

 ovules, as in the left half. Erase guide lines when the 

 diagrams are completed. 



By constructing the diagrams as here directed the parts 

 of the flower will be represented as continuous tissues, as 

 they should be. There should not, for instance, be a line 

 separating the ovules from the placentae, or the pistil, 

 stamens, petals, and sepals from the receptacle. Unless 

 one has good judgment of distance and proportion the 

 guide lines and points here suggested will be found neces- 

 sary for the required degree of accuracy. 



The chief features of irregularities in irregular flowers 

 should be indicated in the cross and longitudinal diagrams. 



Taking the violet for an ex- 

 ample : in the longitudinal dia- 

 gram the spur of the lower 

 petal, one of the nectaries pro- 

 jecting into the spur, the one- 

 sided stigma, and the anthers 

 with sterile tips conniving 

 around the style should be 

 shown in right proportion and 

 position. In the cross diagram 

 the spur of the lower petal and 

 the nectaries projecting into it 

 should be shown, and the fact 

 that the stamens are syngene- 

 sious should be shown by the 

 close proximity of the anthers and the continuous line from 

 the back of one anther to that of another (see Fig. 78). 

 In the larkspur, to take another example of an irregular 



Fig. 78. 



A, longitudinal, and B, cross dia- 

 gram of the flower of the violet. 



