POLYPODIUM FALCATUM. 

 SICKLE-LEAVED POLYPOD, OR LIQUORICE FERN. 



NATURAL ORDER, FILICES. 



POLYPODIUM FALCATUM, Kellogg.— Frond deeply pinnatifid, segments alternate, long lance 

 falcate, alternate, acuminate, doubly serrate, upper and lower divisions smaller by decrees, 

 terminating above in a long slender acumination. Sori numerous, twenty to twenty four 

 in two rows, one on each side of the mid-rib, rachis glabrous, from one to one and a half 

 feet in height. Root compressed tuberculate, one-fourth to one-eighth inch broad, greenish 

 russet color, branching laterally, radicles numerous, rhizoma often covered with scales. 

 (Dr. Kellogg in the Proceedings of the California Academy of Sciences, for December, 

 1854 ; see also Eaton's Ferns of N'orth America.) 



|N a recent work on a curious order of water plants known 

 as Chara — "Characeae Americanae" — the author, Dr. 

 Allen, quotes a distinguished student of the lower orders of 

 vegetation, Alexander Braun, as saying: "So long as I knew but 

 few forms of the GymnopodccB, their distinction was easy, but 

 when it became necessary to distinguish sixteen or eighteen 

 forms, I concluded to consider them all varieties of a sinele 



o 



species." This extract from one of the most celebrated of 

 German botanists shows that even those who have penetrated 

 the deepest into the mysteries of plant life have no definite idea 

 of what determines a species. If some accident had destroyed 

 all the individuals comprising a dozen of the intermediate forms, 

 so as to leave only the extremes, we see that Braun would have 

 regarded these extremes as distinct species ; but because the 

 intermediates had not been destroyed, and thus affording a 

 chain of close relationships, they are all regarded as of one 

 species. 



Now most botanists have had the experience with ferns that 

 Braun had with Characece. The less we know of any species the 



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