1916] 
BURT—PISTILLARIA THAXTERI 405 
toplasmie contents and differentiates into a simple basidium 
somewhat clavate in form, 13-17 4-44 и, when fully mature, 
which bears four spores upon short sterigmata (figs. 5 and 
6). The spores are hyaline, even, slightly flattened on one 
side, pointed at the base, 5-934 и (fig. 7). No cystidia, 
hairs, or organs other than basidia have been found in the 
hymenium. 
This fungus is remarkable not only for its minute size— 
and it is by far the smallest known species of the toadstool 
kind—but also for its extreme simplicity of structure. A few 
hyphae extend out together in a compact bundle from the 
vegetative mycelium, and at a little distance from the sub- 
stratum simply branch and terminate in basidia bearing the 
usual basidiospores. No additional accessory, supporting, or 
secretory organs of any kind are differentiated, nor is there 
any perceptible differentiation into cortical and medullary 
regions in the fructification, nor any curvature of the fertile 
hyphae so that the basidia will be directed towards special 
cavities or towards the substratum; on the contrary, the 
whole fructification is as simple as a sheaf of wheat. A few 
hyphae stand out together from the substratum — probably 
for mutual support—and produce as simply and directly as 
possible their complement of basidia and basidiospores, and 
form both distinct stem and pileus of the simplest possible 
structure. The primordium of the pileus in its ontogeny in 
more highly developed species is not simpler. 
Quelet1 published under the name Pistillina hyalina Quelet, 
n. gen. and sp. the description of a fungus closely related to 
the American species which I am describing. P. hyalina is 
ten times as large as our fungus, clearly visible to the naked 
eye, and has elongated, aculeate spores. Quelet’s genus Pis- 
tillina is regarded as a subgenus under Pistillaria of the 
Clavariaceae by Saccardo.2 While Pistillina appears to be a 
needed genus for such species as that for which it was founded 
and for the present American species, still the few species 
* Champ. Jura et Vosges, Suppl. 10, Assoc. Fr. Avanc. Sci. 9: 671. pl. 8. f. 12. 
1880. 
? Syll. Fung. 6: 759. 1888. 
