No. 104.] 59 



plant. These variations make it difficult to accurately describe the 

 species and to satisfactorily identify them from the published descrip- 

 tions. Some of them, by reviving under the influence of moisture 

 and by the tenacity of their substance, indicate an affinity with the 

 genus Panus and its allies. Some of the larger stout-stemmed species 

 occasionally have the stem nearly or quite central in which case they 

 miglit be taken for species of Tricholoma, though their liguatile in- 

 stead of terrestrial habitat would bean indication of their real affinity, 

 but not a wholly reliable one, since some species of Tricholoma grow 

 on wood. By their white spores they are separated from the otherwise 

 similar Claudopodes and Crepidoti. Two species, P. sajndus and 

 P. euosmus have pale lilac-tinted spores, but these can scarcely justify 

 the removal of these plants to any genus having colored spores, since 

 they would harmonize no better there than here. Indeed there is 

 room for doubt if either of these supposed species is more than a 

 variety of P. osireatus. Several species have valuable esculent quali- 

 ties. Fries 'has divided the genus into three sections, which for 

 convenience we have adopted in the arrangement of our New York 

 Pleuroti. He names them respectively, Excentrici, Dimidiati and 

 Eesupinati. 



Synojisis of the Species. 



Stem eccentric pileus entire or marginate behind 1 



Stem none or short, pileus sessile or not marginate behind 7 



1. Lamellae adnate or emarginate, not decurrent ... 2 



1. Lamellae distinctly decurrent 4 



2. Lamellae white 3 



2. Lamellae yellow P. sid^ihtire aides. 



3. Odor farinaceous, spores ellii^tical P. Ugnatilis. 



3. Odor not farinaceous, spores globose P. ulmarms. 



4. Pileus slightly areolate P. subareolatus. 



4. Pileus not areolate 5 



5. Spores dull lilac , . .P. sapidus. 



5. Spores white , 6 



6. Lamellae anastomosing at the base P. ostreatus. 



6. Lamellae distinct at the base P. salignua. 



I. Pileus never resupinate, generally with a short lateral stem or stem- 



like base 8 



7. Pileus at first resupinate, generally sessile 11 



8. Pileus viscid when young or moist . ... P. serotinus. 



8. Pileus not viscid 9 



9. Lamellae gray, subdistant, stem not compressed P. tremulus. 



9. Lamellae wliite, crowded, stem compressed .' 10 



10. Plant growing on the ground P. spnfhulntns. 



10. Plant growing on decaying wood P. petaloides. 



II. Pileus white " 13 



11. Pileus not white 13 



12. Pileus one inch or more long P. porrigens. 



12. Pileus small, less than one inch long or broad P. septic us. 



13. Lamellae white or yellowish P.atroccBruleus. 



13. Lamellte cinereous, livid-brown or blackish 14 



14. Pileus even or slightly striate on the margin P. atropellitus. 



14. Pileus plicate-striate, 'black .' P. nigcr. 



14. Pileus striate, cinereous or livid-brown P. striatidus. 



Pileus entire or luith a thin margin on one side, stem disti?ict, eccen- 

 tric or lateral. 



