11 



from n. The apices of veins or veinlets are 

 said to be clavate when thickened like a club. 



Reproductive Organs. 



1. Receptacle. The sporangia or spore cases 

 are arranged on a projection of tissue termed 

 the receptacle or placenta. Its position on the 

 frond varies. It may terminate a vein or its 

 branches ; it may be on the point where the 

 veins fork, or on the point of union of two 

 or more veinlets, or on the back of a vein 

 or vein let. It presents various forms, being 

 a rounded elevation, or more elongated or 

 conical, or very long and filiform or ridge-like. 



2. Sporangium. (Fig. i).' The sporangia or 

 spore-cases or capsules are the organs which con- 

 tain the reproductive 



spores (sp.). They are 

 minute roundish oval 

 bodies containing a 

 single cavity and are 

 usually stalked, but 

 sometimes sessile. They 

 are encircled by a com- 

 plete jointed elastic ring 

 termed an annulus (an.) 



Or destitute of SUCh 'S*.'- Stalk ; Sp. - Spores. 



