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 flow^er is exceedingly common. The 

 tendency to obliteration seems to increase as Ave advance towards 

 the centi-e of the blossom, owdng, 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, while the 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 fewei*, 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 througliout, althougli 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 tlie Eose, Strawberry, and the greater part 

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

 3^et there are only two in Agrimonia, one or rarely two in Sangui- 

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

 although the flow^ers of the whole order are formed on the pentame- 

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

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

 Avithout 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 Circles. A complete flower, 



as already remarked (41 G), comprises four whorls or sets of organs; 

 namel}', calyx, corolla, stamens, and jiistils. When any of these four 

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

 complate. The non-production of any one or more of the Avhorls is 

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

 when the corolla is present, or rather, Avhen the floral enA'elopes con- 

 sist of only one Avhorl of leaA'es, they are called calyx, AvhateA^er be 

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



