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Fig. 417. Anthoceros 
Left, section through sporangium and surrounding portion of thallus (x 31). 
The lower part of the sporophyte is a foot, above this is a meristematic region, 
and still higher up are progressively older stages in the formation of spores. 
Note the sterile columella in the center and the sterile tissue surrounding the 
spore-bearing portion. In the drawing the sporogenous tissue is darker than 
the sterile tissue. Right: upper drawing, cross section of sporangium showing 
columella in the center surrounded by sporogenous region; the lower drawings 
show successive stages in spore formation as seen in longitudinal section (x 105) 
