190 PRACTICAL BOTANY 



called calyx-tube, which may be regarded as an en- 

 largement of the floral receptacle. 



2. A corolla of five polypetalous petals also inserted 

 on the margin of the calyx-tube, the petals alternating 

 in position with the sepals. 



3. Andrcecium, composed of indefinite stamens, poly- 

 andrpus, and perigynous, i.e. inserted on the margin of 

 the calyx-tube. 



4. Gynoscium, consisting of one carpel, superior : 

 ovules two. 



This is a typical perigynous flower, in which the 

 sepals, petals, and stamens are inserted on the margin of 

 the calyx-tube. 



Compare flowers of Hawthorn (Cratcegus oxyacantha), 

 which belongs to the same natural order : the number 

 of parts is the same as in the above, excepting that the 

 carpels may be one, two, or three. It differs however in 

 the fact that the calyx-tube is adherent to the ovary, 

 and the ovary accordingly is inferior. Compare the 

 Apple. 



V. Examine flowers of the Primrose (Primula vul- 

 garis), or of the hothouse Primula (P. sinensis), and note 

 that it is composed of 



1. Calyx of five sepals, gamosepalous, inferior. 



2. Corolla of five petals, gamopetalous, hypogynous, 

 and alternating with the sepals. 



3. Andrcecium of five stamens, which are inserted 

 on the inner surface of the tube of the corolla (epi- 

 petalous) : they are opposite the petals. 



4. Gyncecium of five carpels, syncarpous, superior: 

 placentation, free-central, ovules numerous. 



This is an example of cohesion of sepals, petals, and 



