ECOLOGICAL ADAPTATIONS OF CERTAIN FERN PROTHALLIA 49 1 
November 4, culture shows chiefly 4-10 celled prothallia. Some 
plants show plates of 2-6 cells. Some distal cells are attenuated with 
the chloroplasts crowded in the extreme end (figs. 4, 23). For position 
of chloroplasts see also figs. 265, 32, 33. 
Figs. 2-18. Camera lucida drawings of prothallia of A. platyneuron grown on 
Knop's solution. (X 240.) See text for description. 
^ November 11. Plants show growth along three lines, increase in 
number of cells in plates or chains and increase in length of attenuated 
cells. Largest plants show 20 cells. Culture removed to light of 0.8. 
November 17. Plants show rapid growth of plates with the 
beginning of apical groups. Attenuated filaments show normal plump 
cells at their distal ends, and in some cases, show divisions preparatory 
to plate formation (text-figs. 5, 6, 11, 12). 
November 25. Plants show continued growth as last noted. 
Some show plates up to 40 cells where no attenuation had taken place, 
and up to 20 cells at the tips of attenuated cells. Some filamentous 
forms show branches (text-figs. 7, 8, 9, 10). 
December i. Continued growth as above. Culture returned to 
reduced light, .011. 
