(COROLLA. 53 



The calyx is generally of a rough and thick texture and usually 

 green But there are many exceptions ; the calyx is in some 

 cases coloured,* and the corolla in some green. Linnaeus distin- 

 guishes them thus ; the calyx has its leaves or segments opposite 

 the stamens, while the petals or segments of the corolla alternate 

 with them. 



2. The corolla is wanting in many plants, and therefore, the 

 office it performs, whatever it may be, is either dispensed with, 

 being not essential, or is performed by some other part, 



The uses of this very conspicuous part have not yet been fully 

 explained ; the following have been assigned to it. 



1. To protect the tender and important parts within, especially 

 ft om wet. 



2. To furnish a resting place for insects in search of honey. 



3 To submit the juices to the action of air and light. Dr. Bar- 

 win calls the corolla, the lungs of the stamens and pistils, and with 

 great probability, for it abounds with air vessels. 



St. Pierre supposes the corolla to regulate the sun's influence 

 on the fructification of the plant, by reverberating the solar rays 

 upon the anthers and stigma ; or, in some instances, by sheltering 

 them from too intense heat. 



NECTARY, (nectarium) is the part of the corolla 

 which contains, or which secretes honey. 



Observation. 1. Linnaeus usually called every supernumerary 

 part of the flower Nectary, from analogy only, though he might 

 not, in every case, be able to prove that such parts produced 

 honey, 



2. The nectary is confined to no particular part of the flower, 

 but is extremely various in situation as well as form. It cannot, 

 in all cases, be considered as a part of the corolla. 



In relation to the corolla, nectaries are of four kinds. 



1. A mere cavity in the corolla, as the groove in the claw of the 

 petal of the Lily, and the cavity near the base of the petal in 

 Grown Imperial. 



2. A process of the corolla itself, as the scale of the Ranuncu- 

 lus and the spur of the Violet. 



3. An organ separate entirely from the petals, but of a similar 

 texture and colour, as in Columbine, JLquilegia. PI. 14. fiq-. 3. 



4. An organ separate from the corolla and dissimilar iiT struct- 

 ure, as in Jack-in-a-bush, Nigella, and Monk's-hood, Jlconitum. Fig. 5. 



The following are some of the forms of the nectary. 

 1. Spur or horn-shaped, (nectarium cornicnlaium*) 



* Coloured is here technically used for any other colour than green. 



