398 



SUBTERRANEAN ORGANS 



extract, causing in the latter case, the formation of a crystalline deposit of 

 filicic acid and deterioration of the preparation. Male fern is said to lose its 

 activity when kept ; a good sample should show a green and not brown colour 

 in the transverse section. 



Filicic acid crystallises in pale yellow plates insoluble in alcohol, and sparingly 

 soluble in ether. Heated with zinc dust and sodium hydroxide methylphloro- 



glucin is produced, a reaction which 

 indicates an analogy with rottlerin 

 and kosin. 



Filicin is the name given to an 

 amorphous modification of filicic acid 

 said to be its anhydride. 



Filixnigrins are brown or black, 

 amorphous, inactive substances and 

 are decomposition products of the 

 other constituents of the rhizome. 



Although a number of substances 

 have been isolated from male fern 

 rhizome our knowledge of its vermi- 



fuge constituent 

 complete. 



is still far from 



Uses. Male fern rhizome has a 

 powerful toxic action on tape- 

 worms, which it kills and expels. 

 In large doses it is an irritant 

 poison. 



Substitutes. Although the male 

 fern is a common British fern, 

 there are several others that closely 

 resemble it and might be gathered 

 in its place. Of these the most 

 important are A. Filix-fcemina, 

 Roth, the lady fern, and D. 

 spinulosa, O. Kuntze, the shield 

 fern. 



The rhizome of A. Filix-fcemina 

 may be easily distinguished by the 

 number of bundles in the leaf- 

 base, for whilst the male fern has 



from seven to nine the lady fern has only two large ones. Moreover, 

 the lady fern produces no secreting cells in the parenchyma of rhizome 

 or petiole. It has decided anthelmintic properties, and contains 

 filicic acid and possibly filmarone also. It is seldom, if ever, found 

 in the commercial drug. 



The rhizome of D. spinulosa is more difficult to distinguish, as 

 it contains secreting cells similar to those of the male fern, and about 







FIG. 218. Intercellular spaces in the 

 rhizome of Male Fern, showing the 

 secreting glands, T>, and secretion, S. 

 p, cortical parenchyma containing 

 starch -grains. Magnified 240 diam. 

 (Vogl.) 



