[Vol. 12 



334 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



Specimens examined: 

 California: Pinehurst, E. E. Bethel, 26273 (in Mo. Bot. Gard. 



Herb., 55437); Redwood Park, W. H. Long, 1851b, type (in 



Mo. Bot. Gard. Herb., 55065). 

 Mexico: A. Dampf, comm. by J. R. Weir, 63537 (in Mo. Bot. 



Gard. Herb., 63710). 



103. P. tabacina Burt, n. sp. 



Type: in Burt Herb. 



Fructifications effused, adnate, tawny olive to snuff-brown, 

 the hymenium becoming cracked and showing in the fissures the 

 concolorous subiculum, the margin thinning out, colored like the 

 hymenium; in structure 150-400 y. thick, tawny olive throughout, 

 2-layered, with the layer next to the substratum composed of 

 loosely interwoven, even- walled, colored hyphae 3-3^ \i in 

 diameter, nodose-septate, not incrusted, and the hymenial layer 

 about equal in thickness to the other, with its hyphae densely 

 crowded together in a palisade layer and bearing basidia and 

 sterigmata and containing some somewhat colored spores; 

 cystidia not incrusted, cylindric, 6-8 (x in diameter, protruding 

 up to 80 \l; basidiospores hyaline, even, 6-9 X 2J^-3 [l, copious; 

 slightly colored spores 9 X 3 \l are present in the deeper portion 

 of the hymenial layer of the type specimen. 



Fructifications 2-9 cm. long, 1-23^ cm. broad. 



On decaying coniferous wood and bark of logs. Wisconsin, 

 Colorado, Washington, and Oregon. July to November. Rare. 



P. tabacina is distinguished by its tobacco color throughout and 

 hyphae and cystidia lacking incrustation. It lacks the radiate 

 filamentous margin of P. filamentosa of somewhat similar color 

 as well as the hyphal incrustation of the latter. The presence 

 of colored spores in the subhymenium is suggestive of Stereum 

 rugisporum, a species of the same color, occurring on coniferous 

 substrata in the same regions, and more abundant material may 

 show that P. tabacina is the thin, first-stratum stage of the 

 latter, but the fructifications at hand are closely adnate to the 

 substratum rather than loosely connected with it by the to- 

 mentose layer characteristic of many resupinate Stereums. 



Specimens examined : 



