58 THE POLYPORACEAE OF WISCONSIN. 



deep when fully mature, or with occasional longer masses of pores ris- 

 ing above the general surface, 2 to 2.5 cm long ; spores copious, brilliant 

 yellow, oval, smooth, 6 by 4 or 5 microns. 



Large growths of this plant were found in November 1889 on pieces 

 of bur-oak which were broken out of the top of a large tree, by the wind, 

 near the shore of Lake Mendota. The fungus grew under the bark 

 and in the fissures of the wood. At places near the top, about 60 feet 

 from the ground it seemed to have completely surrounded the trunk. 



The plant is entirely resupinate; the subiculum — whenever it is 

 found — is extremely thin, dirty- white becoming brownish; it more 

 often appears to be obsolete. The pores are angular, at first appearing 

 as shallow folds, whitish then lengthening into teeth or tubes forming 

 a somewhat uneven surface. As my specimens grew around an up- 

 right trunk the tubes are very oblique. The become yellowish-black 

 with age. The spores which are characteristic here are golden-yellow 

 and very abundant, covering the plant and wood near by, giving all a 

 yellow color. They measured about 6 microns by 4 to 5 microns and 

 were nearly oval in outline. 



Old specimens might be taken for an Irpex. The tubes are about 

 1 to 1.5 cm. in length and are very brittle. Its habit is similar to that 

 of Irpex ohliquus. 



This species is the same as Poria xantlwspora described by Under- 

 wood (28) in 1893. Ellis and Everhart (8) described it under the 

 name Mucronoporus Andersoni in 1890. Our specimens agree quite 

 well with no. 910 Fungi Columbiani. 



Poria obducens Pers. 



Effused, incrusting, innate, firm, white, formed wholly of the pores. 

 Pores minute, crowded, equal, distinctly stratified, the older strata pale 

 alutaceous. 



Morgan says that the first year it consists of a thin white separable 

 stratum of crowded pores which become alutaceous late?; farther, that 

 it is rather humid when young, thus differing from P. vulgaris which 

 is always dry and inseparable. 



Our specimens were collected under a decaying log at Blue Mounds, 

 August 18, 1903. They are large, sometimes encrusting the entire 

 trunk, irregular, 2 — 3 mm. thick. They consist almost entirely of tubes 

 The best preserved specimens are pale alutaceous, while the older parts 

 are somewhat discolored and verge towards reddish-brown. 



The distinguishing features seem to be the hard, brittle substance 

 which is inseparable from the substratum, and the stratified tubes. 



