XXX . IXTKODITTIOX. 



but separate below the point where the stigmas or stigmatic surfaces com- 

 mence. 



one simple style, with several stigmas, when united up to the point where 

 the stigmas or stigmatic surfaces commence, and then separating. 



one simple style, with a branched, lobed, toothed, notched, or entire stigma 

 (as the case may be), when the stigmas also are more or less united. In many- 

 works, however, this precise nomenclature is not strictly adhered to, and con- 

 siderable confusion is often the result. 



130. In general the number of styles, or branches of the style or stigma, is 

 the same as that of the carpels, but sometimes that number is doubled, espe- 

 cially in the stigmas, and sometimes the stigmas are dichotomously or pinnately 

 branched, or penicillate, that is, divided into a tuft of hair-like branches. All 

 these variations sometimes make it a difficult task to determine the number of 

 carpels forming a compound ovary, but the point is of considerable importance 

 in fixing the affinities of plants, and, by careful consideration, the real as well as 

 the apparent number has now in most cases been agreed upon. 



131. The Placenta is the part of the inside of the ovary to w T hich the ovules 

 are attached, sometimes a mere point or line on the inner surface, often more or 

 less thickened or raised. Placentation is therefore the indication of the part of 

 the ovary to which the ovules are attached. 



132. Placentas are 



axile, when the ovules are attached to the axis or centre, that is, in pluri- 

 locular ovaries, when they are attached to the inner angle of each cell ; in uni- 

 locular simple ovaries, which have almost always an excentrical style or 

 stigma, when the ovules are attached to the side of the ovary nearest to the 

 style ; in unilocular compound ovaries, when the ovules are attached to a 

 central protuberance, column, or axis rising up from the base of the cavity. If 

 this column does not reach the top of the cavity, the placenta is said to be free 

 and central. 



parietal, when the ovules are attached to the inner surface of the cavity of 

 a one-celled compound ovary. Parietal placentas are usually slightly thickened 

 or raised lines, sometimes broad surfaces nearly covering the inner surfaee of 

 the cavity, sometimes projecting far into the cavity, and constituting partial 

 dissepiments, or even meeting in the centre, but without cohering there. In 

 the latter case the distinction between the one-celled and the several-celled ovary 

 sometimes almost disappears. 



133. Each Ovule (121), when fully formed, usually consists of a central 

 mass or nucleus enclosed in two bag-like coats, the outer one called primine, the 

 inner one secundine. The chalaza is the point of the ovule at which the base 

 of the nucleus is confluent with the coats. The foramen is a minute aperture in 

 the coats over the apex of the nucleus. 



134. Ovules are 



orthotropous or straight, when the chalaza coincides with the base (36) of 

 the ovule, and the foramen is at the opposite extremity, the axis of the ovule 

 being straight. 



campy lotr op ous or incurved, when the chalaza still coinciding with the base 

 of the ovule, the axis of the ovule is curved, bringing the foramen down more 

 or less towards that base. 



anatropous or inverted, when the chalaza is at the apex of the ovule, and 

 the foramen next to its base, the axis remaining straight. In this, one of the 

 most frequent forms of the ovule, the chalaza is connected with the base by a 

 cord, called the rhaphe, adhering to one side of the ovule, and becoming more 

 or less incorporated with its coats, as the ovule enlarges into a seed. 



amphitropous or half-inverted, when the ovule being as it were attached 

 laterally, the chalaza and foramen at opposite ends of its straight or curved axis 

 are about equally distant from the base or point of attachment. 



