HYMEXOGASTRACEAE 35 



From R. lutcolus which is somewhat similar in color of fresh plant, abundant 

 fibrils and irregular spores, this species differs in the abundant dark bodies in the 

 peridium. giving to the dried plants a blackish color, by the smaller and more densely 

 packed spore chambers and the plates which divide the gleba into larger areas, each 

 containing several spore chambers. This last peculiarity is the rule in Melanogasler 

 and indicates an affinity to that genus. For a comparison with R. nigresccns see that 

 species. 



6059. Under pines in upland wood? near a branch, rooted in sandy soil under several inches of rotting 

 1 umus, Jan. 30, 1923. 



Rhizopogon maculatus Z. & D. 



Plate 107 



Plants subglobose, ovoid, oblong, or irregularly lobed, flattened, 0.6-1 cm. high by 

 1-2 cm. broad, becoming much smaller upon drying; sordid yellow to deep brown and 

 mottled with lighter colored areas; attached to the earth by one to several conspicuous, 

 dark brown fibers which are free from the peridium below, anastomosing to form a loose 

 web which is innate-appressed laterally and which branches into little fibrils that are 

 sparse and inconspicuous above. Peridium 70-14% thick, composed of two layers: 

 the outer one 30-80/j thick, made up of hyaline, densely entangled hyphae; the inner 

 layer 35-60/z thick, consisting of brown, much entangled hyphae and brown bodies. 

 The outer peridial layer may become worn off or mashed down so as to expose the inner 

 dark layer. Gleba dark grayish to brown, tough, elastic when fresh, becoming hard 

 upon drying; cavities of gleba labyrinthiform, appearing long (up to 1 mm.) and narrow 

 in section, many of them filled with spores at maturity; tramal plates 45-80/x thick, 

 composed of the two hymenial layers which are about 20^ thick and a non-scissile layer 

 of hyphae which are about 3.7/* thick. 



Spores smooth, elliptic, regular, rounded at both ends, 3-3.7 x 5.5-7.4/*. Basidia 

 clavate without gelatinized walls, 4-5 x 10-14/*, with 4-8, usually 8, nearly sessile 

 spores. 



Of the species of Rhizopogon studied by us this plant is nearest R.piceus, but differs 

 from that in the more loosely attached and more conspicuous fibers, in the shorter, 

 elliptic spores which are not angular, in the much smaller basidia without gelatinized 

 walls, and in the double-layered and much thinner peridium. It may also be separated 

 from R. atlanticus, with which it agrees in having a double peridium, by the much more 

 numerous and conspicuous fibers, by the absence of the peculiar cups on the end of the 

 spores, and by the thinner peridium. Our description has been drawn from material 

 preserved in formalin. For a comparison of R. maculatus with others nearly related, 

 see Zeller and Dodge, 1. c, page 5. 



South Carolina. Hartsville. Coker, No. 955. On the surface of damp soil near a branch in a 

 pasture, November 27, 1913. 



Rhizopogon atlanticus Coker and Dodge n. sp. 



Plates 25 and 106 



Plants subglobose, oblong or irregularly lobed, 1-4 cm. thick; young plants pure 

 white then dull yellow toward maturity, not turning rose when rubbed, becoming 

 pinkish cinnamon or sordid yellow-brown upon drying; odor of fresh plants faintly of 

 woods mold, odor of deliquescing plants fragrant like Calycanthus blossoms; superficial 



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