FLORAL FORMS AND THEIR RELATIONS TO INSECTS 35? 



inhabiting the marshes of the southern United States, are seated upon 

 bracts, furnished with hairy appendages, which give a curious flocculent 

 appearance to the whole inflorescence. The morphology of the gynmcium, 

 or pistil, need not detain us long. A pistil also consists of three parts the 

 ovary, the style, and the stigma. Just as the stamen assumes different 

 forms according as its filament is long or short, its connective with or without 

 appendage, its anther-lobes globular or oval, pear-shaped or linear, etc., etc., 

 so the form of the pistil varies in accordance with analogous diversities in 

 the ovary, style, and stigma. The mode of insertion of the style is also a 

 cause of variation. It may spring either from the top of the ovary, when 

 it is terminal ; or from the side, when it is lateral ; or from the base, when 

 it is basilar. Sometimes it is entirely absent, and then the stigma rests 

 upon the ovary, and is said to be 

 sessile. 



The style, indeed, is not an 

 essential part of the pistil; the 

 stigma is. It will be remembered 

 that the latter is the organ which 

 serves for the detention of the 

 pollen-grains. Nature, as might 

 be guessed, has all sorts of devices 

 for facilitating this object, and 

 hence the multitudinous forms of 

 stigma peltate, plumose, penicillate, 

 petaloid, etc. which the pistils of 

 flowers present. 



It should be added that the 

 relative position of the calyx, 

 corolla, and stamens to the pistil 

 is a matter of considerable importance. Observe the flower of a Geranium. 

 Here the ovary is superior to the other floral organs, which are attached 

 to or below its base. Such a flower is termed hypogynous, from the Greek 

 words hupo : under, and gune, a woman. Compare these with the sections 

 of the flowers of Rose and Apple, in which, by the more vigorous growth 

 of the axes, a tube is formed around the carpels, and the stamens and 

 perianth are raised so that they stand on the apex of the rim of the tube. 

 The Rose and Apple are perigynous flowers (Greek peri, around, and gune}* 

 In the Begonia and Carrot we have a third mode of insertion. In both 

 cases the ovaries are situated below the perianth they are inferior ; 

 whilst the flowers as a whole are described as epigynous (Greek epi, upon, 

 and gune). 



* In the case of the Rose, each of the carpels has a distinct ovary ; in the Apple the ovary 

 fills the whole cavity of the tube, with the inner wall of which it is fused. The immature 

 " pips " are ovules, not ovaries. 



FIG. 438. APPLE. 



Section through perigynous flower after the corolla has fal 



