This differs from number 1 chiefly in the cushion-like receptacle on which the crowded sporangia are borne, and in the smaller spores. The species originates in a plasmodium at first colorless, then white, followed by salmon or buff tints, which pass gradually into the dark brown of maturity. This peculiar succession of colors is perhaps more diagnostic than the difference in habit. The spores are, however, constantly smaller in all the specimens we have examined, and the stipitate habit very marked.
New England, New York, south to South Carolina, and west to South Dakota; our finest specimens are from Missouri.
3. Tubifera casparyi (Rost.) Macbr.
[Plate XII]., Fig. 9.
- 1876. Siphoptychium casparyi Rost., Mon. App., p. 32.
Sporangia closely crowded, tubular, cylindric or prismatic by mutual pressure, connate, the apices rounded, convex, covered by a continuous membrane, umber-brown; the peridia firm, persistent, minutely granular, iridescent; hypothallus well developed, thin, brown, explanate; pseudo-columellæ erect, rigid, traversing many of the sporangia, and in some instances bound back to the peridial walls by slender, membranous bands or threads, a pseudo-capillitium; spore-mass dark brown or umber, spores by transmitted light pale, globose, reticulate, 7.5–9 µ.
This is Siphoptychium casparyi Rost. In Bot. Gaz., XV., p. 319, Dr. Rex shows that the relationships of the species are with Tubifera; that the so-called columella is probably an abortive sporangium, the so-called capillitial threads having no homology with the capillitial threads of the true columelliferous forms. It is a good species of Tubifera, nothing more. The tubules are shorter than in either of the preceding species; the spores are darker, larger, and more thoroughly reticulate.
The plasmodium is given by Dr. Rex, l. c., as white, then "dull gray tinged with sienna color," then various tones of sienna-brown, to the dark umber of the mature æthalium.
New York, Adirondack Mountains; Allamakee Co., Iowa.