GEOLOGY OF LA SALLE COUNTY. 



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C. microphyllum, Ach. Thallus small, fuscous- 

 o'reen, or olivaceous, orbicular, diffract or effuse, 

 microphylline, lobes often granulate, crenate at 

 centre, apothecia abundant, small, urceolate, 

 rufescent, flat, thalline margin entire, concolor- 

 ous. Spores sub-muriform. Ach. Syn., L., 

 310. On ash, Deer Park. 



G. flaccidum, Ach. Thallus dark green, or olive- 

 green, lobes large, expanded, buUate, entire, 

 with concolorous granules, undulate plicate, 

 paler beneath, apothecia small, sessile, disk 

 rufescent, margin entire. Spores ovoid. On 

 elm and calcareous rocks, Vermillion river. 



C. tenax, Sw., Ach. Thallus thin, lobes wide, ap- 

 pressed, also ascendant, lead-colored, apothecia 

 often immersed, disk rufescent, the margin entire 

 or rogose. Var. c. of C. pulposum. On lime- 

 stone, Vermillion river. 



C. limosum, Ach. Thallus thin, dark green, scat- 

 tered, slightly crenate, pulpy when wet, apo- 

 thecia rufous, immersed but becoming superfi- 

 cial, margin prominent, entire or somewhat 

 crenulate. Spores in fours in the thekes. In- 

 habits clay soil. Rare. 



C. granosum, Wulf., Schaerer. Thallus small, 

 rigid, gelatinous when wet, lead-colored, lobes 

 ample, rounded or elongated and divided, apo- 

 thecia of medium size, sessile, disk reddish, 

 darR. C. dermatinum, Ach. h. U., 64. On 

 Trenton rock, Coveil Creek. 



C. nigrescens, Huds., Ach. Thallus olive green, 

 lobes bullate, flexuous, monophyllous, apothecia 

 small, disk reddish brown. On elms and lime- 

 stones. 



LEPTOGIUM, Fr., Nyl. Thallus foliaceous, or fru- 



