The North American species of Psathyrella.

1972]

PSATHYRELLA

81

Key to the Sections of Subgenus Candolleana
1. Spores 5-10 u1 long (see P. proxima also). sect. Candolleana.
1. Spores (9-)10-12 fL or more long. sect. Fragilissimae.
Section Candolleana
This is basically the P. candolleana group, and as such needs further critical
study. In this group one can observe the gradual differentiation of brachybasidioles among the various species, as well as a tendency for the spore pigments to be more poorly developed as more southern species are discovered which
show this progression. There is also a tendency toward veilless species-see
P. glandispora Pegler (1966).
Key to the Species of Section Candolleana
1. Spores compressed slightly (7-8 X 3.5-4 X 4-4.6 iu); veil fibrils grayish pallid;
lamellae gray-brown when mature. 42. P. pseudocandolleana.
1. Not as above. 2
2. Pileus dark rusty brown when young and moist; with the stature of
233. P. conopilea; lamellae dark rusty brown when mature. 43. P. rupchandii.
2. Not as above. 3
3. Spores grayish hyaline to weakly brownish hyaline, or nearly hyaline in KOH under
the microscope. 4
3. Spores cocoa-brown or darker in KOH. 6
4. Hyphae of subcuticular region of pileus bright rusty brown in KOH or with
brown wall thickenings or incrustations. 44. P. singeri.
4. Hyphae of subcuticular region of pileus hyaline to dingy ochraceous
in KOH. 5
5. Spores 9-12 X 5-6 a (many 9-10 X 5 t). see 61. P. luteopallida.
5. Spores 7-9 X 4.5-6,; veil absent (but young caps are necessary for verification).
see 242. P. subhyalinispora.
6. Solitary; stipe 14 cm long and 4 mm thick; spores 7-9.5 X 4.5-5.5 IL; known
from Mexico (see 81. P. subagraria also). 45. P. jalapensis.
6. Not as above. 7
7. Spores 5-7.5(-8) X 3.5-5 A, (see 50. P. hymenocephala also) 8
7. Spores 7-10(-11) X4-5,u (see 58. P. huronensis also). 10
8. Spores 5-6.5(-7.5) X 3-4.2 Iu, smoky umber in KOH but soon fading to
hyaline; lamellae pale yellow when young. 46. P. thiersii.
8. Not as above (see 411. P. subochracea also). 9
9. With a compact mat of mycelium at the base of the stipe; pileus radiately
rugulose near the margin. 47. P. rugoproxima.
9. Lacking a mat of mycelium at the base and pileus surface smooth or nearly so
(see 406. P. olivaceocystis also). 48. P. incerta.
10. Outer veil pinkish buff and its hyphae yellow in KOH as revived and viewed
under the microscope. 49. P. rogueiana.
10. Not as above (see 410. P. sublongispora also). 11
11. Pileus typically with a strong cinnamon color tone at first. 50. P. hymenocephala.
11. Pileus pallid to honey-color. 12
12. Spores mostly oblong in face view; solitary on sand.
51a. P. candolleana var. solitaria.
12. Spores elliptic to ovate in face view. 51. P. candolleana var. candolleana.
42. Psathyrella pseudocandolleana A. H. Smith, sp. nov.
Pileus 2.5-4 cm latus, demum planus, glaber, griseo-melleus, ad marginem
appendiculatus; lamellae griseo-pallidae demum fuscae, angustae confertae; stipes
2-4 cm longus, 2-4 mm crassus, pallidus, deorsum griseo-fibrillosus; sporae 7-8x
3.5-4 x 4-4.6,u; cheilocystidia 34-47 x 9-14 /; fibulae adsunt. Typus. Smith 63540
(MICH); legit prope Douglas Lake, Michigan.