North American species of Mycena.

80 NORTH AMERICAN SPECIES OF MYCENA

38. Taste very bitter; at least some cystidia with highly refractive content in fresh condition........................ 54. M. erubescens
38. Cystidia sharply pointed and with homogeneous content; taste
probably mild (forms of M. subsupina may key out here)
50. M. corticaticeps
38. Not as above (cystidia obtuse)................................. 39
39. Spores 7-8 X 3-3.5......................... 47. M. pseudogrisella
39. Spores 4-5 X 2-2.5 u............................. 46. M. Swartzii
40. Gills arcuate to more or less decurrent.............. 174. M. speirea
40. Gills ascending-adnate to hooked............................... 41
41. Spores 6-7 (8) X 5-6, (4-spored) (M. olivaceobrunnea with paleyellow gill edges may key out here also)... 48. M. subcucullata
41. Spores (8) 9-14 X 5-7, (2-, 3-, 4-spored)...................... 42
42. Rather cartilaginous species usually on decaying wood (the 2-spored
form of M. subcucullata keys out here also)...... 49. M. subsupina
42. Fragile species on humus or debris.............................. 43
43. Spores 7-9 X 5-6,u (4-spored); stature of M. filopes but small (M.
subfumosa may key out here also).............. 12. Msubfusca
43. Spores 9-14 X 5-7, (2-, 3-, 4-spored); stature of M. sanguinolenta
51. M. debilis
SUBSECTION ALBIDAE
16. Mycena setulosa, sp. nov.
Illustrations: Text fig. 5, nos. 8-10.
Pileus 1-3 mm. latus, conicus vel convexus, setulosus, griseo-albus
demum albus; lamellae adnatae, distantes, angustae, albidae; stipes
5-8 mm. longus, filiformis, insiticius, albidus; sporae 7-9 (10) X 3.5 -5.5 u, subellipsoideae; basidia tetraspora; pleurocystidia et cheilocystidia 36-48 X 10-14,u, fusoide ventricosa, apice subacuta. Specimen typicum in Herb. Univ. Mich. conservatum. Legit A. H. Smith,
n. 9739, prope Husky Gap Trail, Great Smoky Mountains, National
Park, Tennessee, Aug. 4, 1938.
Pileus 1-3 mm. broad, conic to convex, the margin appressed
against the stipe, remaining unexpanded, surface pubescent under a
lens from numerous projecting setae, surface even at first, pale watery
grayish white, hygrophanous, fading to dead white, membranous;
lamellae adnate, distant, narrow to lacking (in very small caps),
white, edges pruinose from projecting cystidia; stipe up to 5-8 mm.
long, filiform, inserted on the substratum, base not enlarged or very