STRUCTURE OF FRUIT. 169 



always exist, but reduced to very small teeth. The 

 entire absence of the limb is more visible in those Com- 

 positas without a pappus, as the Daisy, &c. ; the limb is 

 here indicated by a small circular rim, entire or un- 

 equally toothed. 



In other cases the limb is visible at the period of 

 flowering, but it is destroyed or detached naturally at 

 maturity ; we observe this in Epilobium, &e. 



Nyctago and the Marvel of Peru present, in this 

 respect, a phenomenon worth mentioning : the base of 

 the perigone, united with the ovary, forms a kind of oval 

 nut, and the upper part separates immediately above it, 

 after flowering, and falls off, the nut remaining within 

 an involucrum which has the form of a calyx. 



It is not necessary that the calyx should be, strictly 

 speaking, adherent to the ovary so as to form an in- 

 tegrant or apparent part of the fruit ; thus, for example, 

 in the Rose, the carpels are dispersed in a kind of cup, 

 which forms the tube of the calyx ; they adhere to it only 

 by their bases ; after flowering, the calyx and torus unite 

 together, increase in size, and become very fleshy, prin- 

 cipally in the inner part. The internal cellular tissue 

 penetrates between the bony, indehiscent, monospermous 

 carpels, which appear to be simple seeds contained in a 

 pulpy pericarp, whilst they are caryopses embedded in a 

 calyx become fleshy. 



In a great number of plants, and especially in the 

 Monochlamydea?, the calyx or perigone, without adher- 

 ing to the ovary, covers it over so closely that it abso- 

 lutely seems to form part of the fruit ; in this case it 

 sometimes remains membranous, as in Atriplex, and at 

 other times it becomes fleshy, as in Blitum. 



When the calyx, without adhering to the ovary, 

 remains around the fruit in a looser manner than in the 

 preceding case, we are contented to say that the fruit is 



