36 THE GASTEROMYCETES OF THE UNITED STATES AND CANADA 



veins few, not conspicuous, innate appressed, darker colored than the peridium usually 

 attached at base by a single small strand which is not conspicuous, separating very 

 easily from the substratum. Peridium when fresh 300-450/* thick, when dried and 

 resoaked 250/* thick, simple, composed of loosely interwoven, much entangled, en- 

 crusted hyphae, pale under the microscope, if dried in the fresh state, except for an outer, 

 thin, brownish crusty area; easily separable from the gleba which is covered with a con- 

 tinuous white layer of the same tissue which separates the chambers. Gleba white 

 when young, becoming Isabella color to buffy brown, shrinking considerably upon 

 drying and not rarely separating from the outer peri dial layer; cavities very small, 

 almost invisible to the naked eye, about 5-8 to a mm., slightly larger toward the center, 

 narrowly labyrinthiform, hollow at first, then only partly filled with the brown spores; 

 tramal plates 45-95/* thick, hyaline, composed of a narrow central region made up of a 

 few gelatinized hyphae (3-3.9/* thick) and the two hymenial layers. 



Spores 3-3.7 x 7.4-8. 5**, blunt-elliptic, brown in mass under the low power of the 

 microscope, furnished at the base with a large empty cup, formed by a continuation of 

 the spore wall. Basidia inconspicuous, 5.5-7.8/* thick, collapsing early, bearing 4-8 

 sessile spores on the ends, the lower part of the spore becoming the empty chamber. 



This species is near R. truncatus described by Linder in Rhodora 26: 196, 1924, 

 from a single specimen collected by him under hemlocks in New Hampshire. Mr. 

 Linder has kindly furnished us with a section of his plant. The peridium of R. truncatus 

 is described as being 120/* thick and composed of a single layer, while the peridium of the 

 present plant is 300-450/* thick when fresh and up to 250/* thick when dried and re- 

 soaked, and is composed of two layers. The tramal plates of the present plant are much 

 thicker than those of R. truncatus, but have the same arrangement and general appear- 

 ance. The cavities between the plates are exceptionally small in both plants. The 

 basidia are alike except for a slight difference in thickness. The spores of the two 

 plants are remarkable for the genus in being the only spores with apparently truncated 

 ends. If the spores of R. truncatus are examined under an oil immersion objective they 

 can easily be seen to be provided with the same empty chamber formed by a continua- 

 tion of the spore wall as in the spores of the present plant, a point not mentioned by 

 Linder. The cup-like extensions are not so conspicuous as in the southern species 

 where they are easily visible under a high dry objective. The spores of our plant are 

 also longer, narrower and paler than those of R. truncatus. This cup on the spore 

 giving it a broadly truncate base distinguishes these two species from all other Rhizo- 

 pogons. A similar cup is found in Hysterangium and Melanogaster. 



South Carolina. Hartsville. Coker, No. 5999 (type). In damp pine woods just below the surface of 



humus, or a few with upper part exposed, December 25, 1922. (U. N. C. Herb.) 

 Florida. Eustis. At foot of a long leaf pine. Thaxter, coll. 1897. 



Rhizopogon truncatus Linder 



Plates 26 and 106 



This species has recently been described from New Hampshire (Camp Algonquin 

 in Holderness; moist birch woods with scattered hemlocks) and a slide of the type has 

 been kindly sent us by Mr. Linder. The species is closely related to our R. atlanticus, 

 which see for a comparison. 



We translate the following from the original Latin description (Rhodora 26: 196, 

 pi. 148, figs. 3, 5-7. 1924). 



