78 THE AGARICACEAE OF MICHIGAN 



ish at apex, minutely brown-pubescent or velvety, instititious, 

 slightly brown-hairy at insertion, base attached to veins of fallen 

 oak leaves. SPOKES elliptical, 7-9x4-5 micr., smooth, white. 

 In frondose woods. Ann Arbor. 



Section V. Rotulae. Stem instititious, filiform, horny or rigid- 

 setaceous. (Attached to leaves, twigs, etc.) 



51. Marasmius rotula Fr. 



Syst. Myc, 1821. 



Illustrations: Cooke, 111., PL 1129. 



Gillet, Champignons de France, No. 443. 



Berkeley, Outlines, PL 14, Fig. 7. 



Ricken, Blatterpilze, PL 25, Fig. 10. 



Hard, Mushrooms, Fig. 108, p. 143. 



Conn. State Geol. & Nat. Hist. Surv., Bull. 15, PL 5. 



PILEUS 4-10 mm. broad (rarely broader), pliant, hemispherical- 

 convex, subum.bona.te-um~bilicate, white or whitish, umbilicus 

 darker, radiately plicate, glabrous, margin crenate. FLESH mem- 

 branaceus. GILLS attached to a free collar behind, distant, 

 broad, whitish-pallid. Stem 2-5 cm. long, filiform, horny, tubular, 

 black or brownish-black, whitish at apex, entirely naked, institi- 

 tious. SPORES lanceolate-fusiform, 6-9x3-4 micr., smooth, white. 

 ODOR none. 



On fallen twigs, leaves and around base of living trunks, gre- 

 garious. Throughout the State. May-September. Very common. 



Often in great abundance after rains in woods, around shade 

 trees, thickets, etc., and is our commonest Marasmius. Its beauti- 

 fully pleated white cap and black stem cause it to be a striking 

 little plant when moist and fully expanded. Sometimes the plants 

 arise in series along a prostrate black strand, and are then often 

 sterile. 



