The Scottish Naturalist. 6j 



being the well-known medicine for destroying intestinal worms that 

 is prepared from the Male Fern (Z. Filix-?nas), and which is ob- 

 tained also from a few other species. The rootstocks of certain 

 ferns contain a good deal of starch ; and a few of them have been 

 used as food in absence of other articles of diet ; but a bitter sub- 

 stance contained in these rootstocks renders the starch unpalatable. 

 When New Zealand was discovered by Europeans, the Maories fed 

 largely on the rootstocks of a plentiful fern, now regarded as a 

 variety of the Common Bracken (Pteris aquilina) ; but since 

 cereals were introduced into these islands, the fern has fallen into 

 disuse as a food plant. 



The Horsetails or Equiseta are not much employed as orna- 

 mental plants, though such species as E. sylvaticum deserve cul- 

 tivation, nor are they more useful to man than the ferns. Almost 

 the only use made of them is the employment of the dried stems 

 in polishing metals or woodwork ; the amount of Silica in the 

 outer coating of the stems renders them hard and rough, and thus 

 very suitable for smoothing rough surfaces. The Clubmosses 

 or Lycopods are of great interest to botanists, because of the many 

 points of structure in which they stand intermediate between the 

 Flowering plants and the Cellular Cryptogams ; but they afford 

 hardly any useful products. Nor are they hurtful to mankind; for, 

 although some species are said to be poisonous, they are not at all 

 likely to be used as food, or to be a cause of accidents. The 

 Selaginellce are not less interesting scientifically than the true 

 Clubmosses ; while they are deserved favourites in greenhouses be- 

 cause of their elegance and beauty. The small genera Isoetes, Sal- 

 vinia, and Marsilea require little comment ; though M. salvatrix 

 has a peculiar interest in its spores having been used as food by 

 the early explorers of Australia when in danger of famine. 



The highest group of the Cellular Cryptogams, the Mosses and 

 Liverworts, is also of comparatively little economic value to 

 mankind, though of great beauty, and of much interest to botanists* 

 They are not often cultivated, though deserving more attention in 

 this respect ; and they are thus of only secondary importance to 

 gardeners, who use them chiefly as packing materials. The power- 

 possessed by many of the Sp/uiyna of sucking up water like a 

 sponge, and supplying it gradually to plants surrounded with a 

 layer of them, makes them of considerable use in the cultivation of 

 many plants. 



