SUMMARY. 315 



In round numbers we mp.y confidently anticipate 

 that when all the scattered descriptions of Crypto- 

 gamic plants have been collected together the total 

 will not fall far short of eighty thousand, of which 

 the fungi, the only section catalogued up to date 

 save the ferns, attain to half of the total number. 



Baron von Humboldt, in one of his works, which 

 was first published about three quarters of a century 

 ago, gives an estimate of the number of Cryptogamic 

 plants known at that period, which may be interesting 

 for comparison. " If we estimate," he says, " the 

 whole number of the Cryptogamia hitherto described 

 at 19,000 species, as has been done by Dr. Klotsch, a 

 naturalist possessing a profound acquaintance with 

 the agamic plants, we shall have for the fungi 8000 

 (of which Agarici constitute the eighth part) ; for 

 lichens, according to J, von Flotow, of Hirschberg, 

 and Hampe, of Blankenburg, at least 1400 ; for the 

 algae 2580; for mosses and liverworts, according to 

 Carl Muller, of Halle, and Dr. Gottsche, of Hamburg, 

 3S00; and for ferns 3250. For this last important 

 result we are indebted to the profound investigations 

 made by Professor Kunze, of Leipzig, on this group 

 of plants. It is a striking fact that the family of 

 the Polypodiacese alone includes 2165 of the whole 

 number of described ferns, whilst other forms, as the 

 Lycopodiace?e and Hymenophyllacese, number only 

 350 and 200. There are, therefore, nearly as many 

 described species among ferns as among grasses." ^ 

 It will be observed that the least amount of increase 

 has occurred in ferns, which have only advanced 

 * Humboldt, "Views of Nature," p. 33S. 



