Part 5, 1916] AGARICACEAE 299 
broad; surface snow-white to milk-white, glabrous, margin entire to undulate, concolorous: 
lamellae not interveined, of medium distance, moderately broad, white: spores globose, smooth, 
hyaline, 4-5.5 p. 
TYPE Locality: Maine. 
Hapitat: Dead deciduous logs and sticks. 
Distripution: Maine to the mountains of Virginia. 
3. Geopetalum semicaptum (Berk. & Curt.) Murrill. 
Agaricus (Pleurotus) semicaptus Berk. & Curt. Ann. Mag. Nat. Hist. IIT. 4: 287. 1859. 
Pleurotus semicaptus Sace. Syll. Fungi. 5: 384. 1887. 
Pileus irregular, resupinate to short-reflexed, gregarious, 8 mm. broad; surface white, 
pulverulent, margin crenate: lamellae entire, distant, narrow, concolorous: spores cymbiform, 
6. 
TYPE LOCALITY: New England. 
Hasitrat: On dead branches of Betula. 
DISTRIBUTION: New England. 
4. Geopetalum oregonense Murrill, Mycologia 4: 215. 1912. 
Pileus thin, sessile, conchate to flabelliform, convex to expanded, milk-white through- 
out, gregarious on dead wood, reaching 1 cm. broad; surface smooth, glabrous, margin entire, 
incurved when young and on drying: lamellae subdistant, inserted, rather narrow, white, slightly 
yellowish when dry: spores pip-shaped, smooth, hyaline, 6-7 X 3-44: stipe wanting, the 
pileus attached to a small, subglobose, white, tomentose mass. ; 
TYPE Locality: Mill City, Oregon. 
Hasrrat: On fallen dead deciduous branches and logs. 
DIsTRIBUTION: Oregon and California. 
5. Geopetalum geophilum Murrill, sp. nov. 
Pileus thin, fleshy, sessile, more ot less resupinate, conchate, 5-15 mm. broad; surface 
smooth, glabrous, white, dry, mycelioid behind, margin thin, concolorous, entire or Somewhat 
lobed: lamellae of medium breadth and distance, white when fresh, becoming yellowish- 
brown and fragile on drying: spores oblong-ellipsoid, smooth, hyaline, 9-11 K 4-5 yu. 
Type collected on soil by the side of a road in woods near Seattle, Washington, October 20- 
November 1, 1911, W. A. Murrill 702 (herb. N. Y. Bot. Gard.). 
DistRiBUTION: Known only from the type locality. 
6. Geopetalum septicum (Fries) Murrill. 
Agaricus pubescens Sow. Engl. Fungi pl. 321. Hae Not A. pubescens Schrad. 1794, 
Agaricus seplicus Fries, Syst. Myc. 1: 92. 1821 
Pleurotus septicus Quél. Champ. Jura Vosg. 79. 2. 
Geopetalum subsepticum Murrill, Mycologia 4: 215° 1912. 
Pileus small, thin, nearly plane, dimidiate and conchate to subcircular or reniform, sessile 
or with a short, white, pubescent stipe or stipe-like base, gregarious, 6-12 mm. broad; surface 
smooth, pubescent or subpulverulent to glabrous, pure-white, margin undulate or lobed, 
inflexed on drying: lamellae rather broad, subdistant, inserted, white, yellowish-brown on 
drying: spores narrowly ellipsoid, smooth, hyaline, 7-9 & 2-4 n. 
TYPE LOCALITY: Europe. 
Hagnirat: On decaying deciduous wood, leaves, and herbaceous stems. 
DIsrRIBUTION: Northern United States west to Washington; also in Europe 
; Pies Cooke, Brit. Fungi pl. 259 (288) B; Gill. Champ. Fr. pl. 345; 5; Sow. Engl. Fungi 
ol. 
Exsiccati: Ellis & Ev. N. Am. Fungi 2727. 
7. Geopetalum albescens Murrill, sp. nov. 
Pileus very soft, fleshy, appearing water-soaked, dimidiate to subcircular, thin, convex, 
sessile, attached by a narrow base, 2-3 cm. broad; surface hygrophanous, very dull whitish, 
becoming milk-white on drying, glabrous, lightly striate for some distance from the margin, 
which is thin, entire, concolorous, and usually upturned in fresh plants: context very thin, 
white; lamellae rather broad, not crowded, inserted, concolorous with the surface, becoming 
