SUPPRESSION OR ABORTION OF PARTS. 



257 



ceived into the spur of the upper sepal ; the two lateral ones having 

 a small but broad blade raised on a stalk-like claw ; and the place 

 wliich the fifth and lower petal should occupy (marked in the gi-ound 

 plan, Fig. 400, by a short dotted hne) is vacant, this petal being sup- 

 pressed, thereby rendering the blossom unsymmetrical. In Aconite, 

 (Fig. 401, 402) the plan of the blossom is the same, but the upper- 

 most and largest of the five dissimilar sepals forms a helmet-shaped or 

 hood-like body ; and as to the petals, three ai'e wanting altogether 

 (their places are shown by the dotted lines in the ground plan, Fig. 

 403) ; the two upper ones, which extend under the hood, only re- 

 main, and these are so reduced in size and so anomalous 

 in shape that they would not ordinarily be recognized as 

 petals. One of them enlai-ged is exhibited in Fig. 404. 

 Petals, &c. of this and other extraordinary forms were 

 termed by Linnajus Nectaries, an unmeaning or mislead- 

 ing name, as they are no more hkely to secrete honey 

 than ordinary petals are. 



476. The papiUonaceous corolla (472) 

 becomes strikingly unsymmetrical by 

 suppression in Amorpha (Fig. 396). 

 Here the corolla is uniformly reduced to 

 a solitary petal (the standard), the other 

 four petals being totally obliterated. 

 This obliteration is foreshadowed in Ery- 

 thrina herbacea of the Southern States, and other 

 species, in which all the petals except the standard 

 are small and inconspicuous. While the blossom 

 of the common Horsechestnut, although irregular, 

 is symmetrical, so far as respects the calyx and 

 corolla, that of our nearly related Buckeyes gener- 

 ally wants one of the five petals, a vacant place on 

 the anterior side of the flower indicating its absence. 



477. The suppression or abortion of some of the 

 stamens requisite to the symmetry of the blossom is 

 According to the ordinaiy view, the six stamens of 



the flowers of the Mustard family (Fig. 405, 406), where the sepals 

 and jjctals are in fours, is explained by supposing that, out of two 

 circles of stamens, four in eacli, two stamens of the outer circle are 



very common. 



FIG. 404. Oae of the petals of an Aconite or Monkshood, enlarged. 



FIG. 405. Flower of Mustard- 406. Its six stamens and the pistil, enlarged. 



22* 



