SPERM \ TOPHYTES 



233 



pc-~- 



528 



Fig. 520. — Archegonia of Ephedra, showing 

 their elongated form and massive necks. — After 

 Land. 



Fig. 528. — Diagrammatic section of ovule of Ephedra, showing outer integument 

 (pi), inner integument (//) forming the long micropylar tube, the remarkable pollen- 

 chamber (pc), and the elongated female gametophyte (within the embryo sac) with 

 two long-necked archegonia. — After Land. 



