OF THE UNITED STATES. 17 



Podisoma fuscum Duby, Bot. Gall., Vol. ii, p. 881 ; Cramer, Ueber den Gitterrost der 



Birnbiiume, PI. i. 

 Podisoma Sahinae Oersted, Om en saeregen hidtil ukjendt Udvikling, etc., PI. i. 



Sporiferous masses numerous, generally approximated, brownish when dry, dark orange 

 when swollen, a quarter to half an inch high, compressed-conical, or wedge-shaped, 

 upper margin thick, rounded, sometimes notched ; spores roundish ovate, two-celled, fre- 

 quently constricted at the septum, 38/^-53,0. long, by 15jti-22^ broad ; upper cell either 

 nearly hemispherical or obtuse ; promycelia generally four from each cell. Mycelium 

 perennial, causing long swellings of the branches. 



On stems of Juniperus virginiana and J. communis. 



Near Boston (Sprague) ; Amherst, Mass. (Frost) ; Catonvdle, near Baltimore, on im- 

 ported species of Juniperus, (Farlow). Europe. 



This species, although apparently common in Europe, is, in its tjrpical form, rare in the 

 United States. It has frequently been confounded with Gym. clavariaeforme from which 

 it differs in the shape and color of the sporiferous masses, which are in G. fuscum usually 

 thick and wedge-shaped with a blunt margin, and of rather a dark, blackish brown 

 color, especially when dry, whUe in G. clavariaeforme they are rather slender and cylin- 

 drical. It also differs in the shape of the spores, which are shorter and stouter in G. fus- 

 cum, and usually give off four promycelia from each cell. The spores vary considerably in 

 outline, those on the surface being more decidedly oval and with a thick dark cell-wall, 

 while those in the interior of the jelly are more acute and with thinner cell- walls. As 

 is the case with most of the species where the promycelia are given off near the sep- 

 tum, the two cells at maturity retract from one another at the outer margin and only 

 remain slightly adherent at the centre. The mycelium is found principally in the stems 

 which have attained a certain thickness and causes them to swell for a distance of several 

 inches. The sporiferous masses rupture the outer bark in eUiptical spots which may be 

 isolated, or, as is more frequently the case, are rather closely approximated. 



In American catalogues and herbaria one rarely finds the specific name fuscum applied 

 to the present species, but it usually figures under the name Podisoma Juniperi Lk., and 

 occasionally as P. Juniperi Fr., which is incorrect, as there is no proper P. Juniperi Fr., 

 the name given by Fries to the present species being P. Juniperi Sahinae. The name P. 

 Juniperi Lk., it must be remarked, has been rather loosely applied in this country to sev- 

 eral distinct species, and when occurring in catalogues of fungi allowance has to be made 

 for the determination. In Herb. Curtis, for instance, of the different specmiens marked P. 

 Juniperi, Lk., one from Maine is G. clavariaeforme ; one from Pennsylvania (Michener, 

 949) and one from Hillsboro, N. C, collected by Curtis himself, are G. clavipes, and one 

 from Sprague is G. fuscum. Specimens which may with certainty be referred to G. fus- 

 cum are few in number. The specimens of Frost, which I have been unable to examine, 

 were on J. communis. Of Sprague's specimens one in the collection of the Boston So- 

 ciety of Natural History, and one in Herb. Curtis are the true G. fuscum on what appears 

 to be J. virginiana. The spores in Sprague's specimens are rather more slender than in 

 European specimens, being 46^57u long by 15^-19u broad, but in other respects they are 

 quite typical. Whether the P. Juniperi of Schweinitz, Syn. Fung. Am. Bor., No. 3095, is 

 to be referred to the present species or to G. clavariaeforme is uncertain, the original 



