CHAP, v.] RELATIONSHIP AMONGST PLANTS. 165 



order known as Crassulacece, including the stonecrops 

 (Sedum), and houseleek (Sempervivum), it is in many 

 species a difficult matter to say whether the stamens are 

 hypogynous or perigynous ; the same is true of the 

 sundew order (Droseracece). In other instances the 

 stamens of a flower become more or less adherent 

 amongst themselves ; in the mallows and the hollyhock 

 all the filaments grow together, the anthers remaining 

 distinct, whereas in composite plants the anthers are 

 grown together, the filaments remaining distinct. All 

 the changes undergone by stamens from the fundamental 

 hypogynous position and perfect freedom from each 

 other, bear directly on the subject of insect- fertilization. 

 Returning to the pistil or central and terminal portion 

 of the flower, we find that the two conditions of apo- 

 carpous and syncarpous, depending on the freedom or 

 adherence of its component parts, called carpels, are 

 again connected by intermediate conditions as seen in 

 the saxifrages. The pistil varies considerably in struc- 

 ture and appearance in different plants, but the three 

 following parts, clearly shown in the primrose, fig. 46, 

 are usually present. The lower swollen portion, which 

 contains the ovules or unfertilized seeds, is the ovary ; 

 this is surmounted by a slender stalk-like body, the style, 

 which in turn is terminated by the knob-like stigma. 

 The ovary is the indispensable portion, which, after the 

 fertilization of the ovules then called seeds undergoes 

 important changes, often increasing considerably in size, 

 and is then known as the fruit; hence it will be observed 

 that ovule and seed are names applied to the same organ 

 at different stages of development ; the same remark 

 applies to the terms " ovary " and " fruit." The stigma is 



