82 



PLANT MORPHOLOGY 



Within the swollen tips of some of the branches are numerous flask- 

 shaped pits or chambers, called conceptades, each with a pore-like opening 

 (Fig. 70). Sperms and eggs are produced inside the conceptades, the 

 sperms in antheridia and the eggs in odgonia. The antheridia are oval 



^^ 



Fig. 70. Longitudinal section of a conceptacle of Fucus furcatus, showing oogonia in 

 various stages of development, small branching filaments bearing antheridia, and numerous 

 paraphyses, X 100. 



and sac-like; they appear on special branching filaments that arise from 

 the Avail of the conceptacle (Fig. 7L4). Each antheridium produces 64 

 small, laterally biciliate sperms. The antheridium is unicellular and, 

 when young, is uninucleate. The number of chromosomes is reduced 

 one-half when its nucleus divides. Free-nuclear divisions continue until 

 there are 32 nuclei. Then the cytoplasm undergoes cleavage to form an 

 equal number of uninucleate protoplasts, each of which divides again to 



