THE LICHEN FLORA OF THE SANTA CRUZ PENINSULA 73 



iV. Thallus fruticose, erect or decumbent, structure radial, corti- 

 cated, with a holdfast Usneacea 



NN. Thallus foliaceous or squamulose. 

 0. Thallus large, attached by a central umbilicus . .Gyrophoracea 



00. Thallus not umbilicate. 



P. Apothecia long-stalked, the podetia simple or branched, 

 naked or covered with leafy squamules. , . Cladoniacecs 

 PP. Apothecia not long-stalked. 



Q. Apothecia adnate by their entire under surface to the 



foliaceous thallus PeltigeracecB 



QQ. Apothecia sessile or elevated sessile. 



R. Medulla lacking or feebly developed; thallus mostly 

 of pseudoparenchyma; aXg^e Scytonema. Ileppiacece 

 RR. Medulla well developed. 



S. Spores spindle-shaped, multilocular; under side of 



thallus usually with cyphellae SlictacecB 



SS. Spores oval or ellipsoid, simple or rarely 2-4 locu- 

 lar; thallus never with cyphellae. 



T. Alga Scytonema PannariacecB 



TT. Alga Pleurococcus or Palmella; apothecia lecan- 

 orine Parmeliacea 



LECANACTIDACEiE. 



Thallus uniform crustaceous, without cortex, alga Trentepohlia. 

 Apothecia circular, sessile or innate ; proper margin lacking, or rudi- 

 mentary, or occasionally well developed; with or without thalline 

 margin. Paraphyses branched, more or less entangled and twining. 

 Represented with us by only one genus. 



XVII. Lecanactis (Eschw.) Wainio. 



Lecanactis Eschweiler, 4, Syst. Lich. Gen., 14. 1824, in part. 

 Lecanactis Wainio. 



Apothecia circular, lecideine, with black proper margin; a thalline 

 margin wanting; hypothecium black, merging into the margin; asci 

 4 — 8 spored; spores colorless, elHpsoid, spindle or needle-shaped, 

 2 — 16 locular. 



Rock and bark lichens, mostly of the warmer regions. 



1. LECANACTIS ZAHLBRUCKNERI Herre. 



Lecanactis zahlhrnckneri Herre, Botanical Gazette, 43: 270. 1907. 



Thallus effuse, of small, irregular (sometines plicate) squamules, 



which at first are scattered but soon become a thick, uniform, tarta- 



