REPRODUCTION IN PLANTS 



99 



cells which produce them, until highly developed REPRODUC- 

 TIVE ORGANS arise. The asexual reproductive cells are formed 

 in SPORANGIA, which may be merely vegetative cells in which 

 the protoplast becomes transformed into a spore, or elaborate 

 multicellular structures set aside for this one function. Simi- 

 larly, with the origin of sexuality, the sex cells arise in GAME- 

 TANGIA, which later are 

 distinguished as ANTHE- 

 RIDIA, or sperm-produc- 

 ing, and ARCHEGONIA, or 

 egg-producing organs. 

 Moreover, although the 

 terms male and female 

 are strictly applicable 

 only to the sperm and 

 eggs respectively, the an- 

 theridia and archegonia 

 are called male and fe- 

 male organs; while a 

 plant body which bears 

 only male reproductive 

 organs is designated as a 

 male plant and one which 

 bears female reproduc- 

 tive organs is known as 

 a female plant. In short, the sexuality of the gametes is 

 reflected back, as it were, to the organs and then to the 

 individual which bears them; although actually the gametes 

 are the only sex cells. If this is kept clearly in mind it will 

 obviate confusion in considering the remarkably specialized 

 secondary features which sexuality imposes on the bodies of 

 higher plants and animals. (Fig. 52.) 



We may now recapitulate before proceeding to further 



FIG. 52. A Brown Alga, Ectocarpus. A, 

 portion of a filament with a sporangium and a 

 liberated spore; B, portion of a filament with 

 a gametangium and a liberated gamete. (From 

 Coulter.) 



