88 PART 1. — ORGANOGRAPHY. 



the funiculus located near the middle of the straight body of the 

 ovule and pointing in a direction at right angles to it, as in Fig. 

 272 ; and an anatropous, or inverted ovule, is one whose chalaza 

 is at one end, and hilum and micropyle adjacent to each other 

 at the opposite end, as in Fig. 273. In the latter two kinds, the 

 funiculus is adherent to the body of the ovule for a portion of 

 its length ; it is this adherent portion that is called the rhaphe. 

 Inverted, or partly inverted, ovules are much more common than 

 straight or bent ones. 



Practical Exercises. 



Study the flowers of the following plants with reference to the pistils : The 

 loppy, the Stramonium, the Lily, the Pumpkin, the Rose, the Hollyhock, and 

 the Indian Corn. Determine (1), the parts of the pistil present in each case ; 

 (2) whether the pistils are apocarpous or syncarpous, and if the latter, state the 

 degree of union ; (3) the placentation of the ovary — that is, whether it is parie- 

 tal, axile or free central ; (4) to what degree, if at all, the ovary is adherent to 

 adjacent organs ; (5) the position and shape of the style ; (6) the position and 

 shnpe of the stigma ; (7) the arrangement of the ovules in the ovary ; and (8) 

 the shapes of the ovules. 



In studying the ovules and placentation, the student should make careful 

 longitudinal and transverse sections of the ovaries with a very sharp knife ; 

 they may then usually be studied satisfactorily by means of a good lens, but in 

 some cases, where the ovules are quite small, the compound microscope will be 

 indispensable. 



CHAPTER XII.— POLLINATION AND FERTILIZATION. 



Pollination. This consists in the conveyance of the pollen 

 from the stamen to the pistil in such a manner as to produce fertil- 

 ization, or cause the setting of seed. Until recent years it was gen- 

 erally supposed that most flowers possessing both stamens and 

 pistils were self-fertilizing — that Nature's design in placing the 

 two organs so near together was to make sure of bringing the 

 pollen in contact with the stigma of the same flower. There are, 

 indeed, some instances in which this is the case, and such flow- 

 ers, since they are habitually self-fertilizing, are called autoga- 

 mous. But flowers of this kind are now known to be com- 

 paratively rare, and cross-fertilization, or allogamy, that is, the 

 fertilization of the pistil by pollen derived from another flower, 



