herre: lichen flora 381 



most of these are transition forms which are probably so modified 

 by their habitat as to lose their typical characters and only physi- 

 ological studies could place them properly. 



This paper concludes my studies of the lichens of the Santa 

 Cruz Peninsula as a separate unit. A work on the lichen flora 

 of the Pacific Coast states is in preparation and the receipt of 

 material from any state west of the Rocky Mountain divide 

 would be greatly appreciated. The chief factor to be reckoned 

 with now is that of geographical distribution, and it is there- 

 fore important to have as many divergent stations represented as 

 possible. Specimens lent me for examination would be promptly 

 returned, while exchanges would be gladly made and unidentified 

 material named. 



VERRUCAZIA NIGRESCENS Pers. in list. Ann. Bot. 14:36. 1795. We may 

 include here the two following Nylanderian species. 



VERRUCARIA AQUILELLA Nyl. Verrucaria aquilella Nylander, Flora, 59: 237. 

 1876. The variety of Verrucaria nigrescens to which Nylander gave this name 

 has been collected by me on sandstone at Devil's Canon, at an altitude of 2400 

 feet. It has likewise been collected by Dr. Hasse in southern California. The 

 asci are short-ventricose or saccate and measure 11 to 12/x in breadth by 23 to 

 24/x in length; when treated with I the thecium is bluish^ then yellow or tawny 

 in color; the spores are smaller than in nigrescen proper, being from 4.4 to 5.8yu 

 in breadth and 11.7 to 17.5^ in length. 



VERRUCARIA FUSCO-CINERASCENS Nyl. Verrucaria fusco-cinerascens Nyl. 

 P'lora, 59: 310. 1876. This obscure lichen, said by Leighton to be "apparently 

 only a state or form of V. nigrescens," occurs on sandstone along the sea coast 

 near Pigeon Point. The thallus is thin, effuse, of minute dark brown or reddish 

 brown uneven areoles, which may be aggregated into a continuous crust or scat- 

 tered and nearly disappear. The spores measure 12 by 28,u in our specimens. 

 Not really separable, except in color, from V. nigrescens. 



VERRUCARIA AETHIOBOLA Wahlenberg. Verrucaria aelhiobola Wahlb. in 

 Supplem. Ach. Meth. Lich. 17. 1803. Thallus thin, smooth, continuous, effuse, 

 forming dark brown stains on the rocks; no chemical reactions. Apothecia very 

 numerous, hemispherical, rather prominent, more or less immersed, black, 

 minute, 0.3 to 0.1 mm. in diameter; perithecium black, dimidiate; paraphyses 

 wanting; asci cylindrical, pyriform, or variously swollen and irregular, 10 to 14ju 

 broad by 32 to 40/i long; hymenial gelatine blue with I, the spores vinous red, 

 quickly fading to yellow; spores elliptical, 4 to 6.8^ broad by 12 to 15/u long. On 

 rocks in the hills east of Los Gatos, at an elevation of 1500 feet and upward. A 

 European lichen recorded by Dr. Hasse (who has kindly determined this specimen 

 for me) from Santa Monica, California, but apparently not otherwise noticed by 

 American authors. 



