l7g THE AGARICACEAE OF MICHIGAN 



503. Hebeloma longicaudum Fr. 



Byst Myeol., 1821. 



Illustrations: Cooke, 111., PI. 415. 



Gillet, Champignons de France, No. 309. 

 Berkeley, Outlines, PI. 9, Fig. 2. 

 Bicken, Blatterpilze, PI. 33, Fig. 2. 



I 'ILEUS 3-6 cm. broad, convex-expanded, subumbonate, glabrous, 

 viscid (moist), even, somewhat irregular, pale ochraceous-tan, becom- 

 ing whitish. FLESH soft, watery, white. GILLS arcuate-adnate 

 then emarginate, medium broad, narrowed behind, crowded, whitish 

 then pale clay-color, edge minutely fimbriate. STEM 5-10 cm. 

 long, 1 -9 nun. thick, white, equal, subbulbous below, stuffed then 

 somewhat hollow, fragile, fibrillose-striate, mealy at apex or through- 

 out. SPORES obliquely-elliptical, inequilateral, narrow at one end, 

 smooth, 12-15x6-7 micr. CYSTIDIA none. Sterile cells slender. 

 slightly enlarged at base, numerous on edge of gills. ODOR 

 scarcely noticeable or none. TASTE mild, not of radish. 



Gregarious. In or near cedar and tamarack swamps, sometimes 

 on sphagnum, sometimes on rich humus. Ann Arbor, New Rich- 

 mond. September-November. Infrequent. 



The white stem, medium size, lack of cortina and large spores 

 distinguish this species. The white-stemmed species of Hebeloma 

 are quite distinct from those with sordid or brownish stems, 

 although the former may become dingy or brownish by handling. 

 The gills are at first adnate-decurrent and often do not become 

 emarginate until late maturity, a character found in several other 

 Bpecies. European authors do not agree upon the size of the spores 

 for this species and usually give smaller spores; but our plant 

 agrees so well with descriptions and the figures referred to above 

 that it seems best to place it here. It differs from H. elatum, for 

 which Massee gives large spores, by its lack of a radish odor, and 



he smaUer average size of the pileus. Two other related species 

 with persistently white stems were found at New Richmond: (a) 



tad a more slender stem up to 9 cm. long, tapering downward, 

 flocculose at apex, elsewhere innately fibrillose-striate; its pileus 

 s up to . cm. broad, yellowish ochre on disk and white on margin; 

 -ills pather broad : odor none, (b) was smaller, with a stem about 

 5 cm. long, hollow and torn-scaly as in H. sinapizans; its cap was 

 testaceous-tan and it had a radishy odor. Both forms had spores 

 9 12 \ 5 6 micr. in size. They need further study. 



