FAMILIAR LESSONS IN BOTANY. 119 



formed with as many cells as the ovary. In this com- 

 pound ovary, the placentce will all be brought together in 

 the axis of the compound pistil. These cells you at once 

 see are made by the union of the walls of the carpels. 

 These divisions or partition walls are called (11) dissepi- 

 me7its. As these are made by the union of two carpels, 

 they consist, in consequence, of two partitions, and often 

 split into two parts. In consequence of abnormal growth 

 from the dorsal suture, these divisions sometimes become 

 greater than the number of the carpels, and are then called 

 (12) false dissepime7its. 



You have been told that a single carpel produces a single 

 cell, two or more carpels two or more cells. In some 

 plants, compound pistils or carpels frequently produce 

 single cells. These are further distinguished as (13) axile 

 and 2ya'rietal placentae. In the first the ovule occupies the 

 center or axis of the pistil ; in the second it is borne on 

 the walls. 



An ovary that can be seen by looking into the bottom of 

 the flower, is said to be (14) superior. When only the 

 summit can be seen at the bottom of the flower, and is 

 united with the receptacle, so as to be looked for under- 

 neatli the flower, it is (15) inferior. 



Section II. — Ovule. 

 The ovule consists of three parts : a small central body 

 called the (16) nucleus; this is enveloped in a double 

 covering, the inner, called the (17) sectcndine, the outer 

 (18) primine. The nucleus adheres to this sac by its 

 base, its summit being free. This double covering has an 

 aperture corresponding to the free summit of the nucleus, 

 which aperture is called the (19) micropyle. The point or 

 base where the nucleus adheres to the double covering, is 

 called the (20) chalaza. The point where the ovule is 

 attached to the placenta, by the thread or (21) funiculus, 

 is termed the (22) liihtm. 



