ESSENTIAL FLORAL LEAVES. IOI 



The pistil of primrose, consisting of five united carpels, presents 

 a case of very close union, where the true state of things can 

 only be inferred from analogy. 



Adhesion. — Mention has already been made of gynandrous 

 stamens (p. 95). The most important example of union between 

 pistil and other structures is presented by the epigynous flower 

 (p. 81). Take, for example, a snowdrop, female flower of vege- 

 table marrow, or bloom of fuchsia. Immediately beneath the 

 calyx a green swelling will be found, which careful examination 

 shows to be the ovary, containing seed rudiments or ovules. By 

 examining flowers of different ages, it will be seen to become the 

 fruit. The most reasonable explanation supposes an inferior ovary 

 like this to be formed by an intimate union between it and a 

 cup-shaped floral receptacle (cf fig. 37). If a Calif ornian poppy 

 (Eschscholtzia), which is an orange-coloured flower commonly 

 cultivated, is cut accurately in half, its ovary will be seen partly 

 embedded in a shallow cup formed by the receptacle. It is, so 

 to speak, becoming inferior. 



Where, as in hypogynous and perigynous flowers, the ovary is 

 free, i.e., attached to, but not fused with, the receptacle, it is said 

 to be superior. 



External Characters. — The simplest kind of pistil is found in 

 gymnosperms. Examine one of the large green cones found upon 

 the Scotch fir in early summer. With some difficulty the scales 

 crowded upon it can be detached. Look at the upper surface of 

 one of them, and observe, close to the end that was attached, a 

 pair of small oval whitish elevations (tig. 45, E). These are 

 seed rudiments or ovules. That part of a carpel to which ovules 

 are attached is termed a placenta, and this very frequently forms 

 a more or less considerable outgrowth. In this particular case 

 the carpels proper are extremely small, and the scales making up 

 the cone are extremely large placentas. Note that but for the 

 overlapping of adjoining scales the ovules would be quite unpro- 

 tected. This condition is characteristic of gymnosperms, which 

 owe their name to it. 



The ovules of angiosperms (fig. 48), on the contrary, are situated 

 in a closed chamber, the ovary. It will be the simplest plan first 

 to consider apocarpous pistils, and afterwards syncarpous ones, 

 which are more complex. An apocarpous pistil is either mono- 

 carpellary or polycarpellary, i.e., made up respectively of one and 

 more than one carpel. Papilionaceous flowers are examples of 

 the former class. Take, for example, a pea flower, and strip oft' 

 the corolla and diadelphous stamens, leaving the pistil behind. 

 It consists of a laterally flattened ovary, from which a curved rod 

 projects. This is the style, and at its tip there is a small sticky 



