— 12— 



Our fern ranges from Arkansas and the Carolinas to Canada. 

 North of its range there is a species that very much resembles it, 

 called the holly fern (P. lone hit is). It bears its sporangia on 

 the backs of ordinary fronds, and so may be easily distinguished. 

 This is also evergreen. 



A third species — P. Braunii—\s found in Canada and spar- 

 ingly in the Northeastern States, in mountainous regions. It is 

 taller than its relatives and more finely divided. It resembles 

 some of the wood ferns, but need never be mistaken. 



The Polystichums may be separated from all our other ferns 

 as follows : 



Sori round, on the backs of the fronds and covered 

 with a circular membranous indusium attached 

 by the depressed centre. 

 Frond pinnate. 



Fruiting part reduced, . . . P. acrostichoides. 

 Fruiting part not reduced, . . . P. lone hit is. 



Frond twice pinnate, P. Braunii. 



— IV. N. C. 



RESTING OF OPHIOGLOSSUM. 



IF the several notes on Ophioglossum that have recently appeared 

 have not conclusively proven that the species rests for a season, 

 they have at least aroused an interest in the question, which 

 further observation, now that attention has been called to the sub- 

 ject, is likely to definitely settle. 



Something analogous to this resting runs through a great 

 portion of the Ophioglossaeeee. It manifests itself in Botrychium 

 Virg internum in the large number of sterile plants that always 

 occur. Since many of these are larger than fertile plants near 

 by, it maybe conjectured that these are really mature plants that 

 are taking a year off, so far as the production of spores are con- 

 cerned. The same phenomenon is found in most of the Botryeh- 

 iums, and is especially noticeable in our other common species — 

 B. obliquum — where sterile fronds usually greatly outnumber the 

 others. 



As to Ophioglossum, the behavior of other members of the 

 genus may throw some light upon our species. It is interesting 

 to know that some forms produce numerous adventitious buds 

 from the roots, and that this forms the chief means of propaga- 

 tion, the prothallia being seldom formed. Our species is known 

 to occasionally produce these buds. It is possible that they re- 



