The Natural System of Botany. 79 



afford a very decisive character. When these are distinct from 

 each other, the ovary is apocarpous, and when they are united 

 into one, it is syncarpous. There are few natural orders in 

 which one of these conditions is not invariable, to the exclu- 

 sion of the other ; so that plants bearing a general resemblance, 

 but differing in this respect, may be at once referred to their 

 proper place. The position of the ovary in respect to the 

 calyx is also to be considered. When the ovary is inferior, 

 the calyx is superior, and vice versa. Some ovaries are 

 divided by partitions, and some have but a single cavity. 

 When an ovary consists of but one carpel, it of course can be 

 only one-celled ; but there are syncarpous ovaries which are 

 also one-celled. This is owing to the obliteration of the parti- 

 tions, or dissepiments, originally formed by the adhering car- 

 pels. When this occurs, the ovules are attached to a central 

 column, leaving an empty space between themselves and the 

 wall of the ovary ; or they are attached to the wall itself, 

 leaving a cavity in the centre. The point of attachment of 

 the ovules is called the placenta, and this in the first case is 

 central, and in the second, parietal. These are distinguishing 

 characters of several orders. Other marks of distinction are 

 found in the enlargement of the receptacle on which the car- 

 pels are situated, and in the varieties of form, substance, and 

 manner of opening of the ovary when ripe, but these are not 

 of the highest importance. The definite or indefinite number 

 of the ovules is often regarded, but their position in the ovary 

 is much more essential, and is one of the most valuable forms 

 of structure to be taken into account. Those which stand 

 upright in the ovary are termed erect, those which hang from 

 the upper wall are pendulous, and some other intermediate 

 positions occur. The substance in the seed, which surrounds 

 the embryo, or rudiment of the future plant, is called albumen. 

 The presence or absence of this is a character of importance, 

 particularly when it constitutes nearly the whole bulk of the 

 seed. In orders whose seed consists almost entirely of albu- 

 men, it is very uncommon to find plants whose seed is destitute 

 of it ; but when its quantity is less, and the embryo nearly or 

 quite equals it in size, the character is of minor importance, and 

 an order may contain some genera whose seed is quite filled 



