il(j THE PISTILS. [lesson 18. 



LESSON XVIII. 



MORPHOLOGY OF PISTILS. 



300. The Pistil, when only one, occupies the centre of the 

 flower ; when there are two pistils, they stand facing each other in 

 the centre of the flower ; when several, they commonly form a ring 

 or circle ; and when very numerous, they are generally crowded in 

 rows or spiral lines on the surface of a more or less enlarged or 

 elongated receptacle. 



301. Their number in a blossom is sometimes expressed, in Sys- 

 tematic Botany, by terms compounded of the Greek numerals and 

 the Greek word Used to signify pistil, in the following way. A flower 

 with one pistil is said to be monogynous ; with two, digynous ; with 

 three, irigynous ; with four, tetragynous ; with five, pentagynous, and 

 so on ; with many pistils, polygynous, — terms which are explained 

 in the Glossary, but which there is no need to commit to memory. 



302. The Parts of a Pistil, as already explained (234), are the 

 Ovary, the Style, and the Stigma. The ovary is one essential part : 

 it contains the rudiments of seeds, called Ovules. The stigma at 

 the summit is also essential : it receives the pollen, which fertilizes 

 the ovules in order that they may become seeds. But the style, the 

 tapering or slender column commonly borne on the summit of the 

 ovary, and bearing the stigma on its apex or its side, is no more neces- 

 sary to a pistil than the filament is to the stamen. Accordingly, there 

 is no style in many pistils : in these the stigma is sessile, that is, rests 

 directly on the ovary. The stigma is very various in shape and 

 appearance, being sometimes a little knob (as in the Cherry, Fig. 

 213), sometimes a small point, or small surface of bare, moist tissue 

 (as in Fig. 254-256), and sometimes a longitudinal crest or line 

 (as in Fig. 252, 258, 267, 269), and also exhibiting many other 

 shapes. 



303. The pistil exhibits an almost infinite variety of forms, and 

 many complications. To understand these, it is needful to begin 

 with the simple kinds, and (o proceed gradually to the complex. 

 And, first of all, the student should get a clear notion of 



304. The Plan or Ideal Structure of the Pistil, or, in other words, of 

 the way in which a simple pistil answers to a leaf Pistils are either 



