1923] Fruit-body of New Parasitic Rhizopogon 103 



fruit-body. After full size is reached the mass of rootlets which has 

 occupied by far the greater part of the body is quickly attacked and 

 destroyed by the internal fungus threads and their place is taken by 

 the gleba. In this invasion of the pine tissue the fungus sends first 

 single threads that force their way between the pine cells, as shown 

 in lower figure of plate 4; and then later by repeated branching of 

 these cells the fungus invades in almost solid sheets, as shown in the 

 upper figures of plate 5 and in figure 1 of plate 7. First the 

 cortex region and then the xylem region is completely destroyed. 

 After maturity first the hymenium and then the entire gleba under- 

 goes deliquescence and becomes a dark brown, tasteless slime with a 

 faint odor of iodoform ; a very small sub-glebal portion remains sound 

 for a time, but later it too deliquesces. The very delicate peridium 

 soon water-soaks; the outer layer collapses; the inner layer remains 

 for a time as a thin, delicate membrane, the plant then having the 

 consistency of a minute bladder filled with a thin, dark jelly. Later 

 this thin coat disorganizes to allow the escape of the slime. 



The true position of this plant is somewhat doubtful. The partly 

 subterranean habit, absence of a capillitium, gleba not becoming a 

 powdery mass, and the indehiscent peridium, would place it in the 

 Hymenogastrineae. The absence of a sterile columella excludes it 

 from the Secotiaceae. Fischer's (4) drawings of the j^oung fruit-body 

 of Hysterangium superficially resemble sections of our young plants, 

 but only superficially for the branching central portion of Hysteran- 

 gium is made up of fleshy strands of fungal material; while this ap- 

 pearance in our young plants is due to the roots of the pine. These 

 roots later disappear entirely. In the Hysterangiaceae the whole in- 

 terior of the fruit-body develops from these fleshy strands and the 

 tramal plates radiate tow^ards the peridium. In our plant growth is 

 from without in, and the tramal plates do not radiate towards the 

 peridium. These are characters of the Hymenogastraceae. In this 

 family the presence of the root-like strands below the fruit-body and 

 the absence of the papilla at the end of the spore exclude our plant 

 from Hymenogaster; while the smooth, fusiform spores exclude it 

 from Octaviania, Hydnangium, Sclerogaster, and Lycogalopsis. The 

 absence of the gelatinous mass in the glebal chambers excludes it from 

 the genus Leucogaster ; and the hollow chambers with the well defined 

 hymenium exclude it from Melanogaster. The soft, loosely woven 



