290 



PLANT LIFE. 



arching leaves (fig. 331). In the same cluster there may be 

 spermaries, or these may be on a different part of the same 

 plant, or on another plant. 



Fig 



33 ?• • 



Fig. 331. — Longitudinal section through the tip of a shoot of a moss (Funaria hygro- 

 metrica). st, stem ; b, leaves protecting the ovaries a. Magnified ioo diam.— After 

 Sachs. 



Fig. 332. —A vertical section of the gametophyte of a fern (Pteris serrulata). g, vege- 

 tative tissue of gametophyte, with chloroplasts ; e, body of ovary sunk in gameto- 

 phyte, surrounding the spherical egg; n, neck projecting and curved; m, mucilage 

 formed by disorganization of canal cells and escaping, having pushed apart terminal 

 cells of neck. Magnified 260 diam. — After Strasburger. 



392. Fernworts and seed plants. — When the gametophyte 

 is a thallus, as in fernworts and seed plants, the ovaries are 

 borne on the surface of the thallus, partially or wholly sunk 

 in its tissue. In the ferns, they arise upon the under surface, 

 near the anterior end (fig. 74), and have the neck only pro- 

 jecting (fig. 332). In the horsetails the ovary is still more 

 deeply sunk. In the selaginellas the gametophytes are male 

 and female, the male arising from the microspores (fig. 315) 

 and the female from the megaspores (fig. 333). Both are 

 small, scarcely larger than the spores in which they grow. 

 The ovary is completely sunk in the female gametophyte and 



