100 SECTION HYGROTRAMA 



Material Studied — maine: Bigelow 4424. Michigan: Smith 

 22072, 22107, 22149, 22306, 26244, 32894 (type, from Mackinaw City 

 Hardwoods, Aug. 6, 1949), 37356, 39377, 50193. 



Observations — This is a striking species by virtue of the changing 

 colors of the pileus, the distant, decurrent, waxy lamellae, the well- 

 developed hymeniform cuticle of the pileus, the persistently yellowish, 

 naked stipe, and the small, globose to subglobose spores. The caespi- 

 tose habit and growth on bare soil under hardwoods is characteristic at 

 the type locality where the fungus has been found regularly every 

 season since its discovery. However, several collections from other lo- 

 cations appear to belong here and were all from black muck under 

 arbor vitae. In these collections the fruiting bodies were scattered, the 

 gills were "Isabella color" ( concolorous with pileus ) at first, and often 

 changed to "tawny olive" before becoming "benzo brown." The per- 

 sistently yellow, naked stipe, however, was characteristic. In view of 

 the changing colors not much emphasis can be placed on a particular 

 tint or shade at any one stage in the development of the fruiting 

 body. The constant features appear to be the persistently yellow stipe, 

 the cap being atomate when faded as well as the initial yellow to olive 

 tint, and the dark violaceous brown end-point of the color change. 



41 



Hygrophorus subfuscescens var. odora Sm. & Hes. 



Sydowia 8: 318. 1954 



Pileus 6-10 mm broad, convex, becoming broadly convex, margin 

 decurved but not inrolled in young caps, "Isabella color" and in age 

 fading to "pale olive buff," finally ashy gray with scarcely any olive or 

 yellow tint showing, no color changes when bruised, glabrous, moist, 

 hygrophanous, atomate when faded. Context "Isabella color" fading 

 through yellow to pallid, waxy; odor very distinctly disagreeable when 

 flesh is bruised, taste mild to slightly farinaceous. 



Lamellae arcuate becoming decurrent, "pale olive buff" becoming 

 somewhat grayer at maturity, soon subdistant or nearly so, moderately 

 broad. 



Stipe short, 1-2 cm long, 1-2.5 mm thick, "deep colonial buff" (or 

 grayer) at apex, no color change when bruised, slightly enlarged 

 above, glabrous, moist. 



Spores 5-6 X 3.5-4 fx, broadly ellipsoid, smooth, yellowish in Mel- 

 zer's reagent. Basidia 35-42 X 6-7.5 /x, 4-spored. Pleurocystidia and 

 cheilocystidia none. Gill trama interwoven, hyphae 2.5 /x broad. Cuti- 

 cle an hymeniform palisade composed of vesiculose-pedicellate to 

 vesiculose-sessile or pear-shaped cells 10-35 X 20-50 /*. No hypoder- 



