Parr 3, 1910] AGARICACEAE 173 
uplifted, naked or more or less tomentose: context brittle, vesiculose, lactiferous, mild or 
acrid in taste; latex white or colored, of the consistency of milk, or if watery, tinged 
with white, or colorless ; lamellae brittle, rather thin, with acute edges, unequal in length, 
often forking, and often becoming darker and pruinose as the plant matures; stipe central, 
never fibrous, sometimes becoming hollow: spores white or yellow, globose to elliptic, in 
many instances echinulate. 
although a few species grow on decaying logs. 
Type species, Agaricus piperatus L. 
Latex white at first. 
Pileus glabrous, smooth or torn or areolate, the margin naked or tomentose. 
Surface not viscid when wet (certain species of XII and XIII often 
appear to lack viscidity). 
Latex very acrid. 
The plants for the most part grow on the ground in woods, 
Pileus white or whitish. I. PIPERATAE. 
Pileus dark-colored. II, RUSTICANAE. 
Latex mild. . 
Flesh thick; stipe stout; wounds unchanging or becoming 
brownish. XVII. LACTIFLUAE. 
Flesh thin ; stipe slender; wounds unchanging or becoming 
yellow. XVIII. CAMPHORATAE. 
Surface viscid. 
Latex unchanging, though wounds may become greenish. 
Viscidity slimy, persisting for a time; latex very acrid. 
Margin entirely naked. 
Pileus some shade of yellow. IV. INSULSAE. 
Pileus some shade of gray, umber, or reddish. V. TRIVIALES. 
Margin at first minutely tomentose. VI. AGGLUTINATAE, 
Viscidity thin, soon disappearing ; latex mild to subacrid. 
Pileus mahogany, brownish-drab, to fulvous. XII. QUIETAE. 
Pileus some shade of gray. XIII. CINEREAE. 
Latex becoming lilac or staining the flesh lilac. VIII. ASPIDEAE. 
Latex becoming yellow. 
Margin downy-tomentose at first; surface slimy-viscid when 
moist; latex acrid. IX. CROCEAE. 
Margin naked or pruinose at first ; surface thinly-viscid when 
wet, soon dry; latex usually subacrid. XI, THEIOGALAE. 
Pileus not glabrous. 
Surface not viscid when wet. 
Latex very acrid; lamellae neither darker nor pruinose with age. 
Surface velvety-tomentose, white or whitish ; latex unchang- 
ing or becoming yellow. I. PIPERATAE. 
Surface scabrous-hairy, olivaceous. II. RUSTICANAE. 
Latex usually mild or tardily acrid ; lamellae darker and pruinose 
with age. 
Pileus minutely tomentose or squamulose. 
Pileus testaceous to fulvous or isabelline. XIV. HELVAE. 
Pileus some shade of gray. XV. GRISEAE. 
Pileus pruinose to velvety. 
Pileus some shade of brown, putty-color, or white; latex 
or wounds sometimes becoming salmon or yellow. XVI. PLINTHOGALAE. 
Pileus some shade of fulvous; wounds sometimes becom- 
ing brownish. XVII. LACTIFLUAE. 
Surface viscid when wet. 
Tatex very acrid, unchanging or becoming yellow. 
Surface more or less covered with long tomentum. III. TORMINOSAE. 
Surface covered with short tomentum, or papillate- 
squamulose. VI. AGGLUTINATAE. 
Latex subacrid to mild, becoming lilac or staining the flesh lilac. VII. SPECIOSAE. 
Latex bright-colored from the first. 
Pileus glabrous, viscid. X. DELICIOSAE. 
Pileus velvety, dry. XVI. PLINTHOGALAE. 
I. PIPERATAE i 
Plants large, the pileus 4-15 cm. broad; margin at length spreading. 
Pileus glabrous. 
Latex white, not staining the wounds. ; 
Flesh thick ; lamellae dichotomously forking, about 2mm.broad. 1. L. piperaia. 
Flesh thin; lamellae very close, about 1 mm. broad. 2. L. pergamena, 
Latex white, drying glaucous-green on the lamellae and broken flesh. 3. L. glaucescens. 
Pileus velvety-tomentoseé. 
Latex white, unchanging; lamellae distant. . . 4. L. vellerea. 
Tatex white, becoming yellow at least where in contact with the 
broken flesh ; lamellae close. ; 5. L. subvellerea. 
Pileus glabrous in the center, having a cottony-roll on the margin, the . 
urface sometimes torn. 6. L. deceptiva. 
