180 



LUSSOICS WITS PLANTS 



205. The fact that the corolla of the disc 

 florets is five -toothed may help us to understand 

 what the' single ray or strap of the ray florets is. 



These rays in both the 

 dandelion and rud- 

 beckia are minutely 

 five-toothed at the end. 

 This suggests that the 

 ray represents the five 

 parts of the corolla, 

 and this is the cus- 

 tomary interpretation. 

 It is evident that if 

 the corolla of a floret 

 were to develop to such 

 a length, it could not 

 spread equal- 

 ly in all di- 

 rections, as 

 a mathematical calculation will 

 prove; it therefore develops in 

 one direction, as a leaf does. 

 206. Another peculiarity of 

 the rudbeckia, as compared with the dandelion, is 

 the absence of pappus. The pupil should now ex- 

 amine the sunflowers; and he has probably already 

 had experience with the barb -like bristles of the 

 "pitch -forks" or "stick-tights," which collect on the 



fuller's teasel. The dry, 

 mature head used for 

 teasing cloth. 



