The veiled species of Hebeloma in the western United States / Alexander H. Smith, Vera Stucky Evenson, and Duane H. Mitchel.

The Subgenus Hebeloma

61

Habit, habitat, and distribution.-Gregarious under a mixture of
spruce and fir with scattered lodgepole pine, Elk Camp, Burnt Mt.,
Pitkin County, Colorado, August 12, 1979 (type, MICH).
Observations.-The spore shape is intermediate between the
bean-shaped and the inequilateral types as seen in profile view. The
species, clearly, is close to H. mesophaeum. The distinguishing features are the fragile, readily splitting stipe, narrow gills, mild odor and
taste, and the dull cinnamon pileus at maturity.
Stirps MESOPHAEUM
Stipe darkening, not splitting.
KEY TO SPECIES
1. Taste truly bitter...............2....................................... 2
1. T aste not as above...................................................... 3
2. Spores 7-9 x 4-5 pLm.......... H. pumiloides var. pumiloides (m) (p. 176)
2. Spores 9-11 x 5-6 pLm........... H. pumiloides var. sylvestre (n) (p. 177)
3. Odor and/or taste raphanoid..............................................4
3. Odor and/or taste not as above........................................ 8
4. Spores 7-9 x 4.5-5.5 pJm; veil copious........................................................... H. strophosum var. strophosum (p) (p. 179)
4. Spores 8-11 x 5-6............................................... 5
5. Veil on fresh specimens buff to cinnamon-buff............ 28. H. sanjuanense
5. Veil pallid to cinereous........................................ 6
6. Lamellae pinkish gray when young; cheilocystidia soon agglutinating;
cheilocystidia small (32-46 x 8-14 x 5-7 pLm), or clavate (+)
and 26-35 x 9-14 pmm....................... H. agglutinatum (b) (p. 163)
6. Cheilocystidia becoming greatly elongated by maturity but
not readily agglutinating............................................ 7
7. Veil copious and remains long persistent on margin of pileus and/or stipe.......................................... 29. H. strophosum var. occidentale
7. Veil thin and scarcely leaving a zone of fibrils on the stipe....................
see 35. H. mesophaeum and varieties and H. mesophaeum var. longipes (h) (p. 170)
8. Veil bicolored (cortina white, outer veil buff)........................... 9
8. N ot as above........................................ 10
9. Spores 7-9 (10) x 4.5-5.5 Im..... H. bicoloratum var. bicoloratum (d) (p. 166)
9. Spores 8.5-11 x 5.5-6.5 (7) pLm.......... 30. H. bicoloratum var. coloradense
10. V eil buff to pale tan................................................ 11
10. Veil cinereous to pallid or white...................................... 12
11. Spores 4-5 pLm broad..................................... 31. H. glabrescens
11. Spores 5-6.5 pLm broad................ H. pseudomesophaeum (1) (p. 174)
12. Many cheilocystidia clavate to vesiculose and 26-35 x 10-15 pLm................................................... 32. H. subviolaceum
12. Not as above....................................................... 13
13. Most cheilocystidia more or less capitate............... 33. H. subcapitatum
13. Most cheilocystidia with obtuse to subacute apices......................... 14
14. Cheilocystidia readily agglutinating....................... 34. H. solheimii
14. Cheilocystidia seldom seen agglutinating... 35. H. mesophaeum and varieties