270 THE FLOWER. 



same circle, than from any other kind of deviation. TH"e tendency 

 to such obliteration increases 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 diminished space 

 the organs have to occupy on the conical receptacle. So, 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 (although from their form they oc- 

 cupy much less room than the petals), 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 pre- 

 sent their typical number in Sedum, and all Crassulaceous plants 

 (Fig. 256, 277, 283-290), are reduced to two, or rarely three, 

 in the allied Saxifragaceous Family, while the other floral circles 

 are in fives. So, in Aralia (the Wild Sarsaparilla and Spikenard), 

 the flowers are pentamerous throughout, although the ovaries of 

 the five pistils are united into one (Fig. 316) ; but in Panax, our 

 other genus of the same family, they are reduced to three in the 

 Ground-nut, and to two in the Ginseng, as also in all Umbelliferous 

 plants. Although the pistils are indefinitely augmented in the 

 Rose, Strawberry, and the greater part of Rosaceous plants, or of 

 the normal number five in Spiraea, yet there are only two in Agri- 

 monia, one or rarely two in Sanguisorba, and uniformly one in the 

 Plum and Cherry, although the flowers of the whole order are 

 formed on the pentamerous or sometimes the tetramerous plan, 

 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. 282), A flower, it may here be added, is isom- 

 erous (that is, of equal members) when it presents the same 

 number in all its floral circles, a term therefore equivalent with 

 symmetrical, and anisomerous when the number of parts is dif- 

 ferent in some of the circles. 



481. As to the stamens, it may be remarked that they are usu- 

 ally symmetrical and regular when the floral envelopes are regu- 

 lar (although the common Chickweed and the Maple are excep- 

 tions to this rule) ; while they strongly tend to become unsymmet- 

 rical by abortion or irregular (that is, of unequal size or shape) 

 when the calyx and corolla are irregular, or the whole is oblique 

 in the bud ; the different stamens at the time of their development 



