Explanation of plate 4 
POLYEMBRYONY IN MATTEUCCIA STRUTHIOPTERIS 
Fic. 1. Outline of aoe section of a prothallium, showing position 
of two — embryos, @ an 
. 2. Longitudinal she section of embryo a of Fic. 1, with sur- 
rounding cells of Lice lliu 
Fi me of b, Fic. 
FIG. 4. Ouititaa of hone: section of prothallium showing position 
of the two embryos a and 3}; a is much larger than 
Fic. 5. Longitudinal vertical section of eapryo a of Fic. 4, with sur- 
rounding colli of the prothallium. 
Fic me of embryo b of Fic. 4. This smaller embryo was abnormal 
and orcbabiy would not have developed into an independent sporophyte. 
