238 



CRYPTOGAMS AND PHANEROGAMS. 



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

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

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

 pores ; in Lauraceee and Berberidaceae, 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 carpels 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 Ophioglossum (Fig. 

 245, compare with Fig. 209). The carpels of the other Cycade$ 

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

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



FIG. 215. A carpel of Cycas revoluta with 5 

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



FIG. 246. Carpel with 2 ovules of 

 Ceratozamia robusta (). 



in the Coniferaa 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 Lycopodinae (Figs. 269, 272, 273 H, compare Figs. 

 230, 239). In Taxus the uninclosed ovule is placed on the apex of 

 a shoot (Fig. 264). In all these plants the ovules are not enclosed 

 by the carpels, that is, they are not enclosed in chambers formed 

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



