3S' THE FLOWER. 



forms of floral structure which occur, we shall be able to trace 

 out the features of the general plan, even among the ■wddest de- 

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

 Some of them are the follo\ving. 



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 (Tguf, three, and /ui^o;, part) in its parts, has 6 stamens, evidently in two 

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

 be regarded as arranged in foiir whorls of fives. Other illustrations will occur 

 to the student. 



b. Some of the entire whorls may have been suppressed. For example, in the 

 primrose there are 5 sepals, 5 petals, and 5 stamens, but the stamens are placed 

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

 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. So7ne of the parts of a whorl may have been suppressed. Such deficiencies aro 

 very 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 rudiment 

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

 stamen is wanting (Fig. 5 ; 5). In the caiTOt, caraway, and all the Umbelliferse, 

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



d. The parts of the same whorl may have been united. Thus the sepals may be 

 united at their edges in diflferent degrees, as in the phlox, pink, &c. Or the petals 

 may be thus united, as in the morning glory : 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. 



e. The organs of different xvhorls may have been conjoined., catising great disturb- 

 ances in the symmetry of the flower. The calyx often, as in the cun-ant, coheres 

 ^vith 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 then* lower part, so as to appear to 

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

 In the Orchis tribe the stamens are consoUdated with the pistil. The term free 

 is used in opposition to these adhesions, 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 imtquaUy 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 tribe 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 struc- 

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

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

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



