1921] The Thelephoraceae of North Carolina 179 



3955. On a standing dead white oak, January 17, 1920. 

 Common on log.s and stump.s. Curtis. 

 Blowing Rock. Atkinson. 

 South Carolina. Hartsville (No. 1522.) Coker. 



4. Stereum frustulosum (Pers.) Fr. 



Plates 18 and 35 



Plant forming small flat, tuberculate, usually crowded bodies 

 which are somewhat expanded at the top. The upper, spore-bearing 

 surface is usually grooved and uneven hke a molar tooth, is brownish- 

 gray in color and nearly glabrous. The sides are blackish brown 

 and rugosely zoned. Flesh brown, very hard and woody, about 

 1.5-3 mm. thick, zoned, each zone representing a renewed growth 

 added over the hymenium of the preceding growing season as in 

 Fomes. 



Spores white, smooth, oval, 2.5-3.5 X 4-5.1[jl. Basidia club- 

 shaped, 5.5-7[x thick, with four very long sterigmata. Cystidia 

 numerous, club-shaped, covered over the distal half with close-set 

 short spines like a giant's club. These spines are not so long in our 

 preparations as in figures by Burt (1. c, p. 227). (See also Lloyd, 

 Letter 51, fig. 565; and Myc. Notes No. 49, p. 696, fig. 1041. 1917.) 

 These peculiar cystidia, together with the perennial habit, indicates 

 a relationship with S. suhpileatum which is, I think, related to S. 

 rugosum. 



The plant is common on decorticated, but still sound and hard 

 oak stumps and logs. Plants in cavities and unexposed to weather 

 may be buffy brown in color, and some of these at least are sterile. 

 As they grow older the plants expand slowly above and if on ver- 

 tical wood may become shghtly shelving above, in such case looking 

 very like a miniature Fomes. 



332. On hard dead wood of white oak, October 4, 1908. 



389. On hard dead oak trunk, October 20, 1911. 



1042. On stump of Liriodendron tulipifera, December 6, 1913. Photo. 

 3814. On oak stump, December 3, 1919. 



4127. On oak stump, February 15, 1920. Plants up to 3 mm. thick, with as many 

 as ten layers. 



Low and middle districts on wood and stumps. Curtis. 

 Blowing Rock. Atkinson. 



