W. C Sturgis — Type- Specimens of Myxomycetes. 479 



and the spores measure 7.8-9.3/i,. On this basis there is not even a 

 varietal difference between D. nigripes and D. xanthopns. The dif- 

 ference expressed by the two specific names is merely one of degree. 

 The color of the stalk is essentially the same in both, though it has 

 a much darker tone in the former than in the latter. 



I have dwelt at length upon these two species in order to call 

 attention to the resemblance existing between them and the type of 

 Didymhan eximium^ Pk., described above. I cannot but conclude 

 that all three represent one and the same species, and that Peck's 

 species, from the standpoint of color, occupies an intermediate posi- 

 tion between the other two. 



On referring to the second specimen distributed by Rex as D. 

 eximiicm, Pk. (N. A. F., No. 2493), we find a most interesting form, 

 apparently the one upon which Macbride and Morgan based their 

 descriptions of that species. In many respects, such as the habit, 

 the size, and the character of the spores, it agrees fairly well with 

 Peck's type ; in others, this is not true. The sporangia have a 

 decidedly yellowish tinge, which, on closer examination, is seen to 

 be due to aggregations of small, spherical, bright yellow granules 

 imbedded in the hyaline wall. The columella is irregularly sub- 

 spherical or flattened and of an orange-yellow color. The capilli- 

 tium consists of delicate, hyaline threads, expanded at the base 

 and often for a considerable distance upwards ; similar expansions, 

 of a more or less fusiform or elongated shape, are of frequent occur- 

 rence in the continuity of the threads. (PI. LX, figs. 16 & 17.) 

 These expansions are filled with spherical, yellow granules similar 

 to those imbedded in the sporangium-wall. The capillitium thus 

 presents somewhat the appearance of a P/i?/sari<m-capillitium. That 

 the granules are not composed of lime, howevei', is seen from the 

 fact that upon treatment with dilute potassium hydrate they die- 

 solve at once and completely, leaving the expanded portions of the 

 thread empty and hyaline. They are evidently organic bodies. 

 The expanded portions in connection with the surface of the 

 columella are conical or tapering and persistent, so that upon 

 dissecting away the looser part of the capillitium the columella 

 appears beset with the long, somewhat spine-like bases of the capilli- 

 tium threads. (PI. LX, fig. 16. Cf. Macbride, 1. c, p. 92.) The 

 spores are rather dark, violet-brown, distinctly spinulose, and measure 

 9.3-1 1.2/A in diameter. This specimen certainly exhibits a marked 

 variation from normal forms of either Didymiiim nigripes, Fr., or 

 D. xanthopus, Fr., in the presence of the peculiar granules of organic 



