Pileus p Pileus conspicuously depressed,4-6cm.broad. M. clitocybiformis Surface of pileus white to plumbeous,umbilicate,12 mm.,broad;stipe twisted,6-8 cm.long. M. tortipes Surface of pileus pale-green. Surface of pileus isabelline or fulvous,sometimes with grayish tints. Pileus 1-3 cm. broad,rarely larger in M.mon-tanus. Pileus convex,rarely fully expanding,umbo- nate or gibbous. Stipe 3 cm. long. Stipe 4-8 cm. long. Pileus gibbous;lamellae crowded. Stipe grayish-pulverulent. M. cinereialbus. Stipe glabrous,polished. M.jalapensis. Pileus prominently umbonate; lamellae not lae not crowded. Pileus plane or depressed,never umbonate. Stipe glabrous. Lamellae white. M. putredinis. Lamellae fulvous. M. coracicolor. Stipe pruinose,becoming subglabrous at times. Stipe 5 mm. thick;species terrestrialM. pruinosisfolius Stipe 1-2 mm. thick;species not ter- restrial. Stipe densely velvety-pruinose. M. cervinicolor. Stipe whitish-pulverulent to subglabrous. Pileus 7-15 mm. broad. Pileus 2-4 cm. broad. Pileus plane. Pileus umbilicate or de- pressed. Pileus 4-7 cm. broad. Lamellae free; stipe 2.5 cm. long Lamellae adnate;stipe 5cm. long. Surface of pileus bay, chestnut,reddish,or ferruginous. Lamellae crowded and connected by conspicuous cuos reticulate veins. Lamellae distant, not conspicuously con- nected by veins. Pileus ferruginous, 4cm. broad. Pileus bay or chestnut, not more than 2 cm. broad. Stipe pruinous to glabrous,2.5 cm. long. Stipe glabrous and shining from the first, 3-6 cm. long. Lamellae about 12-16 in number. M. haematocephalus .7210