1920] 



BURT THELEPHORACEAE OF NORTH AMERICA. XII 83 



stipitate and merismatoid species, of which we have only 5 as 

 against 23 in the warmer southern region. The stipitate and 

 merismatoid species grow sometimes on dead wood and some- 

 times on the ground; all 49 dimidiate and effuso-reflexed species 

 grow on dead wood, causing its decay, and are distributed 24 

 in the northern and 18 in the southern area, while 7 others are 

 the species already mentioned as ranging over both north 

 temperate and tropical areas. 



Key to the Species 



1. Central-stemmed species. Pileus more or less infundibuliform, some- 

 times deeply split on one side, usually stipitate; stem typically central 

 or eccentric but lateral-stemmed forms are also present in many of the 



species 1 



11. Lateral-stemmed species. Pileus dimidiate, flabelliform, or wedge-shaped 

 never infundibuliform attenuated at the base into a more or less 



distinct stem 9 



111. Merismatoid species. Pileoli several, somewhat infundibuliform, wedge- 

 shaped, or strap-shaped, borne on or along a common stem 12 



IV. Sessile species, wholly lacking stem or stem-like base. Pileus dimidiate- 

 sessile, umbonate-sessile, or reflexed, all growing on wood many 

 typically reflexed species may sometimes occur wholly resupinate 13 



1. CENTRAL-STEMMED SPECIES 



1. Fructifications solitary or gregarious 2 



1. Fructifications cespitose 8 



2. Species with pileus always more or less infundibuliform, lacking dimi- 

 diate or other lateral-stemmed forms 3 



2. Species having lateral-stemmed forms occurring more or less frequently 



in collections 5 



3. Neither cystidia nor gloeocystidia present; stem not radicated 4 



3. Gloeocystidia present; growing on the ground, 1^-3 cm. high, 3 mm.-2 cm. in 



diameter; in South Carolina to Brazil 3. S. Ravenelii 



3. Gloeocystidia present; growing on wood; in West Indies to Dutch 



Guiana 4- S. surinamense 



3. Hair-like cystidia present; pileus white, 2-4 cm. high; in New York to Missouri, 



and in Alabama, Washington and California 10. S. diaphanum 



3. Hair-like cystidia present; pileus slightly darker than S. diaphanum, 3-5 



mm. high; in New York U.S. exiguum 



3. Hymenial organs unknown; growing on the ground, with stem continued 



by a long radicated portion which penetrates deeply; in French Guiana 



5. S. macrorrhiza 



4. Growing on wood, 2-15 cm. high and in diameter; upper surface with 



raised, radial ridges; in Gulf states to Bolivia 1. S. caperatum 



4. Growing on wood, 6-11 cm. high and in diameter; upper surface not 



ridged; pileus and stenrvelvety; in South America. . .2. S. hydrophorum 

 5. Neither cystidia nor gloeocystidia present; pileus cartridge-buff to pinard- 



yellow when fresh; in New Hampshire to North Carolina and Tennessee, 



and in Japan 6. S. Burtianum 



5. Hymenial organs unknown; pileus "straw-colored," 1| mm. in diameter; 



stem 4 mm. high; growing on wet ground among moss in Cuba 



7.S. rivulorum 



5. Cystidia present 6 



5. Gloeocystidia present; no cystidia 7 



6. Pileus white, of soft, bibulous texture, 3-5 mm. broad, 5-7 mm. long; 



on bark and mosses in Cuba 8. S. quisquiliare 



