132 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
found in his cultures of Dacryomyces deliquescens (Bull.) Duby, a 
definite fructification of considerable size composed entirely of gemmae, 
which are formed by the hyphae breaking into one- or two-celled 
portions, each capable of vigorous germination. These gemmae 
should probably be classed as oidia. 
Exobasidiaceae. — The whole life history of a Basidiomycete was 
first followed by Woronin (’67) in Exobasidium vaccinii (Fuckel) 
Woronin, a species later cultivated by Brefeld (’89) and Richards 
(’96). If the basidiospores germinate on a substratum less favorable 
than a leaf of the host plant, the germ tubes at once produce clusters 
of rather elongated, fusiform bud cells, which continue to sprout and 
form similar cells at their extremities. This process may continue 
indefinitely with unimpaired vigor, as is shown by Brefeld who fol¬ 
lowed it in his cultures for more than a year. In Exobasidium andro- 
medae Peck, Richards found not only these “small acicular spores 
borne on much branched hyphae among the basidia,” but also a 
second type of conidium, which is larger and is “borne singly on 
rather stout hyphae not occurring with the basidia.” On germination 
both types of conidia produce acicular secondary spores like those 
produced by the germinating basidiospores. 
The Dacryomycetaceae and the Exobasidiaceae are placed among 
the Autobasidiomycetes on account of their unseptate basidia. Yet 
in many respects they are unlike other Autobasidiomycetes and similar 
to the Protobasidiomycetes. Their type of polymorphism, especially, 
recalls that of the Auriculariineae and Tremellineae, viz., in the 
immediate formation of tufts of bud cells or conidia on germination 
of the septate basidiospores, and in the formation of similar bud cells 
or conidia on the young mycelia. Hence, in the succeeding parts 
of this paper these two families will not be considered further in the 
discussion of the polymorphism of the Hymenomycetes. 
Hypochnaceae. — All the genera of this family are of interest in the 
present discussion, since some possess definite conidia, and the exact 
nature of others is rendered uncertain by peculiarities and variations 
of the basidia. 
The most interesting conidia are found in Tomentella, a genus 
which closely resembles Hypochnus, for Brefeld (’89, p. 9) asserts 
that “the distinction between the two genera consists solely in the 
possession of conidial fructifications by Tomentella,” and that the 
discovery of conidia in other species may “enrich Tomentella at the 
