8 Ophioglossaceae 



marginal sporangia which arise from groups of cells. 

 Prothallus tuberous, subterranean with numerous sunken 

 antheridia and archegonia. 



Family OPHIOGLOSSACEAE. Stem short, vertical, 

 sunk in the earth and sending up a few leaves which 

 take several years to develop. 



Sterile leaf-segment pinnate. Pinnules with digitate 

 nerves. Fertile segments branched. Botrychium. 



Sterile leaf-segment simple, entire with reticulate 

 veins. Fertile segment unbranched, spike-like. 



Ophioglossum. 



Division 2. EMBRYOPHYTA SIPHONOGAMA 

 {Phanerogainae auct.). 



Alternation of generations obscured by seed formation. 

 Sporophyte cormophytic, very various, heterosporous. 



The inegaspore {embryo sac) is not discharged from 

 the sporangium {ovule) which after fertilisation ripens to 

 form a seed. 



Microspore {pollen grain) on germination forming a 

 tube. Ant/m'idium represented by a single cell which 

 divides to form two naked generative cells which in 

 the lowest Gymnosperms become transformed into 

 Spermatozoids. 



Subdivision i. GYMNOSPERMAE. Microspor- 

 angia on under surface of sporophylls. Carpels not 

 fused together to form an ovary, thus no stigma is present. 



The microspores {polle^t grains) germinate at the 

 micropile. Seeds naked on the ovuliferous scales or 

 on a direct prolongation of the axis. 



Prothalhis {endosperm) formed before fertilisation. 



