238 



CRYPTOGAMS AND PHANEROGAMS. 



(quadrilocular anthers, Fig. 244). A few, for instance Orchidaceoe 

 and Asclepiadacea?, have only two pollen-sacs (bilocular anthers) ; 

 and in others, such as Solanum and the Ericaceae, they open by 

 pores ; in Lauracere and Berberidacese, by valves. The part of the 

 stamen which bears the pollen-sacs is termed the anther. Most fre- 

 quently this is supported by a stalk known as the filament. 



Carpels. The simplest forms of cai'pels are found in Cycas. 

 In this genus both the foliage and fertile leaves are pinnate, and 

 hence present great similarity ; the ovules (macrosporangia) are 

 situated on the margin of the central portion, just as the sporangia 

 are placed on the edge of the fertile leaf of Opliioglossum (Fig. 

 245, compare with Fig. 209). The carpels of the other Cycadea? 

 present greater divergence from the foliage-leaves, being peltate, 

 for instance, in Zamia and Cemtozamia (Fig. 246). The ovules 



FIG. 215. A carpel of Cycas rcvoluta with 5 

 ovules (s), at half to one-third nat. size. 



FIG. 240. Carpel with 2 ovules of 

 Ceratozamia vobiisto. (i). 



in the Coniferse are situated on the upper side and near the base 

 of the ovuliferous scales, almost in the same position as the spor- 

 angia in the Lyeopodina? (Figs. 269, 272, 273 IT, compare Figs. 

 2:111, :j:!'.i). In '!'., * the uninclosed ovule is placed on the apex of 

 a shoot (Tig. 261). In all these plants the ovules are not encln^'d 

 l>y tin- carpi-Is, that is, they are not enclosed in chambers formed 

 by the turning in of the walls of the carpel, and hence the name 



