40 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



a height of 20-25 cm. Though not so robust in habit as 

 N. 7'itprechtiammi, still some specimens of N. violaceum 

 are vigorous in their growth, branching freely and forming 

 large, handsome plants. The plant is papery or parchment- 

 like in texture, rather brittle when dried, and does not 

 adhere well to paper. 



N. violaceum, as before remarked, agrees with N. 

 ruprechtiaiuim in many morphological details, such as char- 

 acter of branching, general shape and position of sori, and 

 venation; but it may be distinguished from that species by 

 its different color and texture, and the minute differences 

 in size and shape of the sori. 



An extremely wide range of variation may be seen in 

 the amount of dissection which the frond of N. violaceum 

 undergoes. On the one hand, there is found a form in 

 which the frond becomes divided from the base into a great 

 number of slender, much prolonged branches, which divide 

 again and again, until finally the apices of the ultimate 

 branches are prolonged in a flabellate fashion sufficiently to 

 show the specific characters of venation and color. On 

 the othef hand, there occur forms rather broadly membra- 

 nous at base, that divide into a few broadly obcuneate seg- 

 ments cleft from the outer edge into narrower portions 

 which are prolonged into lobes, again exhibiting the charac- 

 ters of the species. Between these extreme types may be 

 found intermediate forms that in some cases vary toward 

 the finely dissected frond, in others, toward the broadly 

 membranous frond. Stunted and weathered plants also 

 occur in considerable numbers in late winter and spring. 

 The frond in these instances is occasionally thickened and 

 rather fleshy, while the sori are gathered into clusters of mar- 

 ginal proliferations or remnants of the former margin. Pro- 

 liferation takes place, though not to the same extent as in 

 N. riiprechtianum. The proliferations are, as a rule, small, 

 and of varying size. They usually bear sori. 



In common with N. rupi'echtianum , N. violaceum chal- 

 lenges attention by reason of the peculiarities of its sori, 

 which exhibit again the same range of variation in regard 



