SECT. 1. ORGANOGRAPHY AND GLOSSOLOGY. 101 



free. In the passion -flowers, the stamens adhere to 

 the ovarium, and the petals to the calyx. 



(102.) Floral Modifications. As an illustration of 

 these, we may state, that the orders of the class Dicoty- 

 ledones, are thrown into four principal groups, two of 

 which are characterised by the circumstances alluded to 

 in the last article. The first of these, the Thalamiflorae, 

 includes those flowers which have their several whorls de- 

 tached, or not adhering together each whorl occupying 

 a distinct position on the torus, as in fig. 89- The sepa- 

 rate parts of the several kinds of whorls, however, may 

 or may not adhere together. This group can strictly 

 include only hypogynous flowers. The next, or the Ca- 

 lyciflorae, includes those orders whose flowers have their 

 petals and stamens adhering to the calyx, whether in 

 the perigynous or epigynous form of the flower. In both 

 groups, all the four floral whorls are almost universally 

 present. Each, however, contains a few examples which 

 cannot be separated from their congeners, but in which 

 the petals are wanting, or are very rarely developed. 



Of the two other groups, one is termed Corolliflorae, 

 where the corolla is monopetalous, and the stamens ad- 

 here to the inside of its tube. This includes only 

 hypogynous flowers. The last group is termed Mono- 

 chlamydese, where the perianth consists of only one 

 whorl, which is almost universally recognised as a 

 calyx. 



(103.) Nectary. The word " nectary," is of very 

 general application, and is used to express some pecu- 

 liar modification in the sepals or petals, by which they 

 assume an unusual form; but more especially, when there 

 is some alteration of structure, by which they are wholly 

 or partially converted into secreting organs, and exude 

 a saccharine, glutinous juice. 



(104.) Mstivation. As the condition of the leaf 

 whilst yet in the bud, is termed its vernation, so the man- 

 ner in which the several parts of the flower lie folded in 

 the flower-bud, is termed their " aestivation." Of this 

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