herre: lichen flora 385 



3000 feet. A European earth-dwelling lichen which is found across the northern 

 half of the American continent. 



LEPTOGIUM CRISTATELLUM (Tuck.) Herre. Collema cristatellum Tuck. 

 Lich. Calif. 29. 1866. Herre, Proc. Wash. Acad. Sci. 7: 378. 1908. A careful 

 study of the thallus of this lichen shows it to be a true Leptogium and not aCollema, 

 a well developed cortical layer being present. In addition to the stations pre- 

 viously recorded, I have found it growing on crumbling sandstone beside the road 

 en route to the Lick Observatory in the inner Coast Range, at an altitude of 

 about 1100 feet. 



PLACYNTHIUM SONOMENSIS (Tuck.) Herre. Pannaria sonomensis Tuck., 

 Proc. Am. Acad. 12: 169 1877; Synopsis, 1: 126. 1882. Thallus forming small 

 to very small orbiculate or irregular dark dull brown patches, which appear to 

 the- naked eye as little more than dirty stains on the rocks; made up of very minute 

 but distinct elongated, terete, linear and many cleft lobes; these more or less 

 tangled and coralloid centrally, but somewhat expanded marginally; beneath 

 white or pale, and smooth; upon a black hypothallus, which is usually obsolete; 

 alga Scytonema. Apothecia minute, lecanorine, sessile; the flat disk soon convex 

 and finally sub-globose, in which case the persistent entire whitish margin may 

 be excluded; color reddish brown and blackening; margin enclosing algae which 

 likewise form a layer beneath the colorless to very pale dusky hypothecium; 

 epithecium broad, umber; thecium colorless, blue with I ; paraphyses, thick, jointed, 

 with enlarged tips; asci much shorter than the paraphyses, clavate, their contents 

 usually not differentiated, 6 to 9m broad by 35 to 41^ long; spores very slender, 

 straight or slightly curved, simple, colorless, 1.5 to 3/x in breadth and 17 to 26^ 

 in length; these measurements are somewhat smaller than those given by Tucker- 

 man. I have collected only sterile specimens in the Santa Cruz Peninsula, at 

 Castle Rock, altitude 3000 feet; on rocks at Alum Rock Park, inner Coast Range, 

 'near San Jose, at an altitude of 500 feet, it occurs abundantly fertile. Collected on 

 various rocks in Sonoma County and also at Yosemite by Bolander. This plant 

 does not agree with any of the genera as defined by Zahlbruckner, as it combines 

 lecanorine apothecia, simple spores, and Scytonema algae. These characteris- 

 tics do not occur together in any genus as defined, but as the separation of the 

 genera of the Pannariaceae should be based primarily upon the alga enslaved 

 rather than upon the spore characters or apothecial structure, I deem it best to 

 call this plant a Placynthium. 



PANNARIA LEUCOSTICTA (Tuck.) Pannaria leucosticta Tuckerman, Proc. 

 Amer. Acad. 4: 404. 1860. Cummings, Williams, and Seymour, No. 270, Decades. 

 North Am. Lichens, Sligo Creek, Maryland. Thallus small to medium, appressed, 

 the radiate lobes expanded marginally, their tips denticulate crenate, upturned; 

 from sub-orbicular becoming effuse; centrally becoming reduced to minute den- 

 ticulate squamules and passing into a granular crust; color whitish gray, changing 

 centrally to brownish or greenish buff; margin of lobes and finally the whole upper 

 surface except the peripheral lobes covered with minute, erect, denticulate, whit- 

 ish, bluish, or concolorous granules; beneath white, and blackening; no chemical 

 reactions. Apothecia numerous, of medium size; appressed, with dentate thalline 

 margin, the flat disk soon strongly convex; color pale to dark red-brown; epithe- 

 cium pale yellow; hypothecium brownish; thecium pale blue, then more or less 

 tawny with I; spores simple, subglobose to broadly ellipsoid, often pointed at one 



