310 NORTH AMERICAN FLORA [VoLumE 9 
4. Leptomyces purpurascens (Berk. & Curt.) Murrill. 
Hiatula purpurascens Berk. & Curt. Jour. Linn. Soc. 10: 293, 1868. 
Pileus thin, plane, 2.5 cm. broad; surface pale-purple, glabrous: lamellae free, broad: stipe 
somewhat enlarged at the apex, glabrous, solid, 4 cm. long. 
TYPE LocaLity: Cuba. 
Hasrrat: On rotten leaves. . 
DISTRIBUTION: Known only from the type locality. 
5. Leptomyces Benzonii (Fries) Murrill. 
Agaricus Benzonii Fries, Elench. Fung. 1: 20. 1828. 
Pileus thin, campanulate to expanded, umbilicate, 2.5 cm. broad; surface pale-reddish or 
brownish, margin striate: lamellae free, approximate, white: spores ovoid, apiculate, 1-guttu- 
Jate, hyaline, 8-11 X 7 w: stipe equal, glabrous, 2.5-4 cm. long, 2-4 mm. thick. 
TYPE LOCALITY: Santa Cruz Island. 
Hasrtat: On logs. . 
DistRIBUTION: Known only from the type locality. 
DOUBTFUL AND EXCLUDED SPECIES 
Hiatula caespitosa Berk. & Curt. Jour. Linn. Soc. 10: 293. 1868. Described from 
specimens collected on logs in Cuba. See Omphalopsis euspeired. 
Hiatula crenulata (Fries) Sacc. Syll. Fung. 5: 305. 1887. (Agaricus (Hiatula) crenulatus 
Fries, Nova Acta Soc. Sci. Upsal. III. 1: 27. 1851.) See doubtful species of Heliomyces. 
Hiatula fragillissima Berk. & Rav. Ann. Mag. Nat. Hist. II. 12: 422. 1853. This 
species has been referred to Lepiota cretacea. 
32. OMPHALOPSIS Earle, Bull. N. Y. Bot. Gard. 5: 425. 1909. 
Agaricus § Omphalia Fries, Syst. Myc. 1: 162. 1821. 
Omphalia Quél. Ench. Fung. 19. 1886. Not Omphalius Roussel, 1806. 
Pileus usually umbilicate with the margin at first appressed, usually solitary or gregarious: 
lamellae decurrent, thin, acute: spores hyaline: stipe central, slender, tubular, with cartilaginous 
cortex. 
Type species, Agaricus campanella Batsch. 
I. SPECIES OCCURRING IN TEMPERATE NorTH AMERICA, EXCEPT THOSE CONFINED TO THE 
PacIFIC COAST 
Pileus white or whitish. : 
Pileus not exceeding 6 mm. broad; surface pure-white. 
Pileus papillate, conic or campanulate. 1. O. papillata. 
Pileus umbilicate. i 
Pileus 2-4 mm. broad. 2. O. pusillissima. 
Pileus 4-6 mm. broad. . O. Rhododendri. 
Pileus exceeding 6 mm. broad, rarely smaller in some specimens of O. 
corticola, O. clavata, and O. immaculata. 
Pileus umbilicate or depressed at the center. 
Surface striate, at least on the margin. 
Stipe 1-2.5 em. long. 
Stipe whitish throughout. 4. O. albidula. 
Stipe partly brownish. 5. O. corticola. 
Stipe 2.5-4 cm. Jong. 6. O. Austini. 
Surface not striate; hymenophore pure-white throughout. 7. O. translucentipes. 
Pileus convex, not depressed at the center. 
Pileus densely cespitose. 8. O. centenaria. 
Pileus not densely cespitose. 
Pileus pure-white. 9. O. immaculata. 
Pileus pallid or cinereous. 
Pileus convex to subplane, not umbonate. 10. O. clavata. 
Pileus convex to turbinate, usually umbonate. ll. O. turbinata. 
Pileus yellow, orange, or ferruginous. 
Pileus yellowish-ferruginous; stipe 2.5 cm. or less long. 12. O. campanella. 
Pileus orange or pale-yellow; stipe 2.5-5 cm. long. 
Pileus 12 mm. or more broad; spores 7.5 X 5 p. 13. O. fibuloides. 
. Pileus 3-10 mm. broad, rarely larger; spores 4-6 X 2-3 yp. 14. O. fibula. 
Pileus olive-green. 15. O. olivaria. 
Pileus grayish-brown or fuliginous. 
