248 



ORGANOGRAPHY. 



former organs are epipetalous their insertion with regard to the 

 pistil depends upon the point where the corolla itself becomes free ; 

 thus, in the Primrose {fig. 529), where the stamens are epipetal- 

 ous and the corolla arises from the thalamus below the pistil and 

 free from the calyx, the stamens, as well as the corolla, are said 

 to be hypogynous. When the stamens adhere to the calyx more 

 or less, so that their position becomes somewhat lateral to the 

 pistil instead of below it, as in the Strawberry, Cherry {fig. 530), 

 and Apricot, they, as well as the corolla, are said to h^'perigynous. 

 When the calyx is adherent to the ovary so that it appears to 

 rise from its apex, the intermediate stamens and corolla also 

 arise from the summit, and are said to be cp^gynous, as in the 

 species of Campanula {fig. 531), Carrot, and Ivy: 



The full understanding of the above terms is of great im- 

 portance in practical botany ; and the arrangements of the 

 organs as thus indicated by them, have been used by De CandoUe 

 and other botanists as the basis of some of the sub-divisions 

 in their systems of classification, as will be particularly described 

 hereafter when treating of Systematic Botany. 



It sometimes happens that the stamens not only adhere to 

 the ovary or lower part of the pistil, as in the epigynous form 

 of insertion, but the upper part of the stamens and pistil be- 

 come completely united also, and thus form a column in the 

 centre of the flower, as in the Orchis {fig. 532), and Birthwort 

 {Aristolochia) {fig. 533) ; this column is then termed the gynosie- 

 mium, and the flowers are said to be gynandrous. 



3. Union. — ^When the stamens are perfectly free and separate 



Fig. 534. Fig. 585. Fig. 536. 



Fig. 537. 



Mci. 5n4. Syntrenesious anthers of a ppecies of Thistle (Cnnlnus). Fig. 



535. Mnnadelphous staineiis of Mallow {Malva). Fig. ?>?S. Monadel- 



ph on s stain ens of "Wood Sorrel (OTalin'), forming a tube round the 



pistil. Fiff.bZr. Male flower of Jrrfrop7;a CitrcffS. c. Calyx, p. Corolla. 



e. Stamens united hy their filaments into a tube, a, which occupies 

 the centre of the flower as there is no pistil. 



