4 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
KEY TO GENERA, 
Paraphyses soon gelatinous, indistinct or absent. 
Spores simple.........2......2.020 22.0 ccc e cece cece anes VERRUCARIA (p. 4). 
Spores not simple. . 
Spores 2 to 4-locular............ 0.000002 THELIDIUM (p. 6). 
Spores muriform-multilocular................ ceeeeee POLYBLASTIA (p. 6), 
Paraphyses permanent, distinct. 
Spores simple............ 0.000000 c eee cece eee THROMBIUM (p. 6). 
Spores muriform-multilocular....................2222--- MICROGLAENA (p. 7). 
VERRUCARIA Scop. 
Thallus crustaceous, presenting the different phases from pulverulent to smooth, 
and either areolate or disappearing. 
e KEY TO SPECIES. 
Apothecia wholly immersed in thallus, only the ostiole free. 
Perithecia large. 
Thallus brownish to dull black................... 7. V. nigrescens. 
Thallus green brown, the color distinct when 
0) 8. V. viridula. 
Perithecia small. 
Thallus green black, thin....................... 9. V. dacryodes, 
Thallus black, finely rimose, thin................ 10. V. maura. 
Apothecia not wholly immersed, sessile or only half 
immersed. 
Perithecia sunken in matrix.......................-- 1. V. caleiseda. 
Perithecia not sunken in matrix. 
Thallus obsolete..............0.00000-0 2c cece eee 5. V. margacea terrestris. 
Thallus present. 
Thallus white or whitish. 
Whitish to light brown. ............2... 2. V. rupestris. 
Creamy white, mealy.................... 3. V. integrella. 
Thallus dull brownish. 
Perithecium concolorous................ 4. V. margacea papillosa, 
Perithecium black...........2222.2.2... 6. V. aethiobola. 
1. Verrucaria calciseda Lam. & DC. 
Thallus pulverulent, whitish, giving its substratum a dull white coating, effuse, 
at times wanting; perithecia brownish black, depressed hemispherical, impressed 
in shallow cavities in the rock; ostiole irregularly poriform; perithecium dimidiate, 
dark brownish black, the amphithecium also dark; paraphyses gelatinous, apparently 
shorter than the asci, these ventricose, about 100 long, 28 x thick; spores 8, colorless, 
simple, ovoid-ellipsoid, while inclosed in the ascus 11 to 13 je long, 8 to 11 x thick, 
when expelled measuring 20 to 24 # by 8 to 11 »; hymenial gelatine staining light 
blue then vinous red with iodine. 
On calcareous rocks at lower and middle elevations in the mountains of Ventura 
and Los Angeles counties. Of wide distribution in North America, also in Europe. 
2. Verrucaria rupestris Schrad. 
Thallus light grayish to dusky leathery brown, granular-furfuraceous; perithecia 
medium small, 0.2 to 0.25 mm. in diameter, numerous, semi-immersed in the thallus, 
the projecting perithecium dull black; spores oblong-ellipsoid, 20 to 27 » long, 7 
to 12 » thick; paraphyses gelatinous, obscure; hymenial gelatine a pale claret color 
with iodine, the spores yellowish. 
