THE ESSENTIAL ORGANS. 



47 



the stigmas. 3d. A partition dividing the cell of a single carpel 

 must be a false one; as occurs in Flax (136). 4th. The PLA- 

 CENTAE, as well as the ventral suture, will be axial. 

 ~~f" 133. Again: the carpels may each be open and conjoined by 

 their edges, as are the petals of a gamopetalous corolla. So it 

 is in the ovary of Violet (137) and Rock-rose (139). In this 

 case, 1st. There will be no partition (unless a false one, as in the 

 Crucifers), and but one cell; 2d. The Placenta will be parietal, 

 i. e.j on the wall of the cell (paries, a wall). 



134. Between the two conditions of axial (or central) and parietal placenta, we find all 

 degrees of transition, as illustrated in the different species of St. Johnswort and in 

 "Poppy, where the inflected margins of the carpels carry the placentae inward, well-nigh 

 to the axis. Moreover, the placentae arc not always mere marginal lines, bat often wide 

 spaces covering large portions of the walls of the cell, as in Poppy and Water-lily ; in 

 other cases, as Datura (168), they become large and fleshy, nearly filling the cell. 



133, Samolus Valerandi, section of flower showing the free axial placenta. 134, Ovary of ScrophuTa- 

 riacear. 133, Ovary of Tulip. 136. Cross-section of ovary of Flax, 5-celled, falsely 10-celled. 137, Ovar> 

 of Violet, 1-celled. 138, Ovary of Fuchsia, 4-celled. 139, Ovary of Rock-rose, 1-celled, 5-carpelled 

 140, Gentianaceae, 2-valved, 1-celled. 



135. A free axial placenta, without partitions, occurs in some 

 compound one-celled ovaries, as in the Pink and Primrose orders 

 (133). This anomaly is explained in two ways first, by the 

 obliteration of the early formed partitions, as is actually seen to 

 occur in the Pinks ; secondly, by supposing the placenta to be, 

 at least in some cases, an axial rather than a marginal growth ; 

 that is, to grow from the point of the axis rather than from the 

 margin of the carpellary leaf, for in Primrose no partitions ever 

 appear. 



136. A few peculiar forms of the style and stigma are worthy of note in our narrow 

 limits, as the lateral style of Strawberry ; the basilar style of the Labiatre and Borrage- 

 worts ; the branching style of Emblica, one of the Euphorbiacesc ; also the globular 



