234 



PLANT LIFE. 



always occurs when they are unequal. A corresponding dif- 

 ference in size is often found between the sporangia con- 

 taining small spores iyDiicrosporangia) and those containing 

 large spores {megasporangia) (figs. 241, 242). 



The sex terms, male and female, applicable primarily to 

 the sex cells, are apjilied also to the organs and to the plants 



Fig. 240. — .S]inrophyte of a club-mfiss f Ar'i'/('^//("/ c^.i7'iit>i)u). l"]ie lioriznntnl stem 

 is densely covered with leaves ; tliose on the erect branch become small and tew for a 

 space; these are succeeded by broader leaves, the sjiorophylls, crowded in a dense 

 spike, s. Half nattiral size. — After Prantl, 



KiG. 241. — Section through three sori of an aquatic fernwort {Sal^'inla >iata>is). 

 Each is covered by a double indusium. /, /, two sori consisting of sporangia con- 

 taining microspores (see hg. 242); a, a sorus consisting of sporangia, each containing 

 one mcgasiiorc. Magnitictl lo diani. — .'\fter Sachs. 



whi( h bear them, so that the microspores are said to produce 

 male plants, and the megaspores lenialc plants. For a fur- 

 ther account of the gamctoph)'le, see ^; 386, 394, 393. 



328. Seed plants. — In the seed ]ilauts this dilTcrentiation 

 of the si)0ies is always found. The microspores are called 



