504 



PHANEROGAMS. 



the upper surface) all those ovules which spring singly or in numbers from the 

 margin or upper surface of carpellary leaves, as those of Cycadeae, Abietinese (?), 

 Liliacese, Umbelliferae, Ranunculacese, Resedaceae, Cruciferae, Leguminosae, &c. In 

 these cases the nucleus would be a new formation on the surface of the lobe, the 

 funiculus would correspond to its base, and the integuments to its upper part folded 

 once or twice round the nucleus in the form of a cup. Only in those few plants in 

 which the ovule has no integument would the naked nucleus or entire ovule corre- 

 spond to this lobe of the carpellary leaf. In the first edition of this book I expressed 

 my agreement with Cramer's view, but with a reservation with respect to Orchideae, 

 being especially influenced by the importance which I then attached to the morpho- 

 logical equivalency of the nucleus in all Phanerogams. Further reflection has, 

 however, deprived this reason of its importance; and I am the more induced to 

 ascribe different morphological significations to the ovules, according to their mode 

 of origin and their position (as has been shown by Magnus, Rohrbach, Hanstein, 

 and Schmitz^), because in Piperaceae, Typhaceae, and Naiadeae, the ovule is actually 

 the terminal structure of the floral axis, and in Naias this terminal ovule is also 

 anatropous. In these statements I not only find the confirmation of my own ob- 

 servations on Chenopodiaceae and Polygonaceae, but they are also in harmony 

 with the theory that the ovules previously described by Payer as terminal are 

 really so. Since, however, it is not my object here to enter into a detailed proof 

 of theoretical matters, it will be suflicient for the present to summarise the various 

 phenomena. 



With respect to position, the following classes may first of all be distinguished: — 



A. Ovules produced on the Carpels and springing from the carpellary leaves ; 



and either 



1. Marginal, from the reflexed margins of the carpels (Figs. 354, 355, 



356, 359); or, 



2. Superficial, from the whole of the inner surface of the reflexed halves of 



carpellary leaves, always apparently with the exception of the mid-rib 

 of the carpellary leaf (Fig. 351). 



B. Ovules produced on the Axis and springing from the prolongation of the 



floral axis within the ovary, the carpels themselves being sterile ; these may 

 be either — 



3. Lateral, when they stand beside or below the apex of the floral axis, 



which either rises as a columella and bears a number of ovules (as in 

 Fig. 360), or is arrested in its development, so that the single ovule 

 appears terminal (as in Fig. 362) ; or, 



4. 2W?jwial, when the apex of the floral axis itself becomes the nucleus 

 (as in Figs. 330, 361, and in Piperaceae, Naias, Typha, &c.). 



To which of these classes the ovules belong in any given plant must be decided 

 in each separate case ; the position on the margin of the carpels is by far the most 

 common among Angiosperms, both the superficial and the axile position belonging 



* These researches have been already quoted. 



