SUPPRESSION OR ABORTION OF PARTS. 259 



are in the blossom of Catalpa (Fig. 409), but their vestiges remain 

 in the form of small sterile filaments, two of which, however, occa- 

 sionally bear anthers, either perfect or rudimentary. 



479. The suppression of a portion of the pistils required to com- 

 plete the symmetry of the flower is exceedingly common. The 

 tendency to obliteration seems to increase as we advance towards 

 the centre of the blossom, owing, doubtless, to the greater pressure 

 exerted on the central parts of the bud, and the progressively di- 

 minished space the organs have to occupy on the conical receptacle. 

 Thus, wliiie tlie corolla, when present at all, almost always consists 

 of as many leaves as the calyx, the members of the stamineal circle 

 or circles are frequently fewer in number, and the pistils are still 

 more commonly fewer, excepting where the axis is prolonged for 

 the reception of numerous spiral cycles. Thus, the pistils, which 

 present the symmetrical number in Sedum, and all plants of that 

 family (Fig. 334, 335, 355, 361), are reduced to two, or rarely three, 

 in the allied Saxifrage family, while the other floral circles are in 

 fives. So, in the Wild Sarsaparilla (Fig. 410) and Spikenard, the 

 flowers are pentamerous throughout, although the ovaries of the five 

 pistils are united into one ; but they are reduced to three in the 

 Ground-nut, and to two in the Ginseng, belonging to the same genus, 

 as also in all Umbelliferous plants. Although the pistils are in- 

 definitely augmented in the Rose, Strawberry, and the greater part 

 of Rosaceous plants, or are of the normal number five in Spiraea, 

 yet tliere are only two in Agrimonia, one or rarely two in Sangui- 

 sorba, and uniformly one in the Plum and Cherry (Fig. 388), 

 although the flowers of the whole order are formed on the pentame- 

 rous, or sometimes the tetramerous plan, and with a strong tendency 

 to augmentation of all the organs. And the Pulse family has, almost 

 without exception, five members in its floral envelopes, and ten, or 

 two circles, in its stamens, but only a single pistil (Fig. 358). 



480. Suppression of one or more whole Cireles. A complete flower, 



as already remarljed (416), comprises four whorls or sets of organs; 

 namely, calyx, corolla, stamens, and pistils. When any of these four 

 circles or kinds of organs are wanting, the flower is said to be in- 

 complete. The non-production of any one or more of the whorls is 

 not uncommon. The calyx, however, is seldom if ever wanting 

 when the corolla is present, or rather, when the floral envelopes con- 

 sist of only one whorl of leaves, they are called calyx, whatever be 

 their apjaearance, texture, or color, unless it can somehow be shown 



