forms of floral structure wliicli occur, we shall be abk^ to trace 

 out the features of the general plan, even among the widest de- 

 viations, and to learn the nature and causes of these deviations. 

 Some of them are the following. ^ 



a. 'One or more additional whorls of the same organ may have been developed^ ' For 

 example, the flower of the Trillium, which, as in most liliaceous plants, is trim- 

 erous (t^s/?, three, and ^sgo-, part) in its parts, has 6 stamens, evidently in two 

 whorls, and in the flower of the cherrj' (No. 2,) there are 20 stamens, which may 

 be regaixled as an-anged in four whorls of fives. Other illustrations will occur 

 to the student. 



b. ^ome of the cnthx whorls may have been suppressedj-i For example, in the 

 primrose there arc 5 sepals, .5 petals, and 5 stamens, hut the stamens are placed 

 opposite the petals.. This is to be attributed to the absence of an intcmiediate 

 whorl of stamens, for in the Samolus, a plant of the same natural order, there is 

 a circle of sterile filaments in the place of the absent stamens (Fig. 5 ; 3, 4). 



c. Some of the parts of a whorl may have been suppressed. Such deficiencies aro 

 veiy common. In the sage, for example, and Monarda, three of the stamens are 

 wanting, in place of which are two rudimentary filaments, and the third radiment 

 makes its appearance in some allied genera.' In most of the Labiatse but one 

 stamen is wanting (Fig- 5 ; .'5). In the carrot, caraway, and all the Umbelliferte, 

 the pistils are reduced from 5, the normal number, to 2. 



d. J^he parts of the same ivhorl may have been united. '. Thus the sepals may be 

 united at their edges in different degrees, as in the phlox, j^ink, &c. Or the petals 

 may be thus united, as in the morning gloiy : or the stamens, as in the mallows 

 tribe ; or the pistils, which is extremely common. In short, scarcely a flower can 

 be found in which some of these cohesions do not occur.j 



e. [The organs of different whorls may have been conjoined} causing great distm-b- 

 ances in the symmetiT of the flower. ^The calyx often, as in the currant, coheres 

 with the whole surface of the ovarium (97), only becoming free at the summit, so 

 that it seems to stand upon it. It is then said (but improperly) to be superior. 

 Again, the stamens adhere to the petals in their lower part, so as to appear to 

 gi-ow out of them; they are then said (improperly) to be inserted into the corolla. 

 In the Orchis tribe the stamens are consohdated Avith the pistil. The term free 

 is used in opposition to these adliesions, just as the term distinct is used in oppo- 

 sition to the cohesion of the same organs with each other. 



f. The organs of the same whorl may have been tmequaUy developed. This is the 

 case in the corollas of the pea and bean tribes, called papilionaceous (Lat. papilio, 

 a butterfly), and in those of the mint tiibe called labiate (Lat. labium, a lip). \ 



g. Again, organs of one kind may have been reconverted into those of another kind, 

 or into leaves. ; Such monstrosities are of frequent occurrence among cultivated 

 plants, and may be regarded as proofs of the present doctrine of the floral strac- 

 tare. In all double flowers, as the rose, peony, tulip, &c., the stamens have been 

 reconverted into petals. By still further changes, all parts of the flower tend 

 towards a leafy character, rendering the resemblance of the flower to an nndevel- 



