THE FLOWER. 



99 



same conditions : i. e. when the calyx is inferior, the free ovary is supe- 

 rior, and vice versa. 



The terms perigynous, &c., and calyeifloral, &c. are in constant use and 

 very convenient, but they may convey false notions as to actual structure. 

 In the perigynous flowers of Kosaceae, for example, such as those of 

 Fragaria, Geum, &c., the stamens really rise from an expansion of the 

 receptacle, forming the so-called throat of the calyx, and in Rosa, Pyrus 

 (tig. 172), and other similar forms the carpels are really enclosed in an 

 excavated receptacle or receptacular tube, from the upper edge of which 

 sepals, petals, and stamens arise. In these cases the receptacle instead 

 of lengthening into a conical extremity becomes tubular. 



Fig. 170. 



Fig. 171. 



Fig. 172. 



Pig. 170. Epigynous flower of an Umbellifer in section; pistil completely inferior. 



Fig. 171. Flower of Saxifrage in section, with a partially adherent calyx and half-superior 



pistil. 

 Fig. 172. Flower of Pyrus in section; pistil inferior, calyx superior, corolla superior, stamens 



perigynous. 



The adherence of stamens to pistils produces what is called the gynan- 

 drous condition, so remarkable a character of the Orchidaceae and Ascle- 

 piadaceae. 



Irregular growth. Irregularity of flowers arising from unequal 

 size, different form, or unequal degree of separation of the organs 

 or whorls is extremely common. Different form and size produce 

 irregularity in the floral envelopes and stamens of many plants 

 where these are free ; and this is often associated with irregularity 

 arising from suppression. The irregular union occurs alone, or is 

 superadded to all the rest when the organs are coherent ; this con- 

 dition is oftenest found in the floral envelopes, in the stamens less 

 frequently, and in the pistils perhaps not at all. 



Irregular polypetalous flowers illustrating this point present themselves 

 in Papilionaceous plants, in Fumariaceae, Violacese, &c. ; irregular poly- 

 sepalous calyces occur in Acomtum, Delphinium, &c. Stamens are gene- 



H2 



