DEVELOPMENT OF THE HELVELLINEAE 
I. HELVELLA ELASTICA 
W.A. McCuBBIN 
(WITH PLATES XIV-XVI AND ONE FIGURE) 
Our knowledge of the developmental stages of the Helvellineae 
has been restricted to the Geoglossaceae, and is mainly due to the 
researches of DirTRIcH (9) on Leotia gelatinosa and Mitrula phalloides. 
Practically nothing is known of the ontogeny of the Helvellaceae 
and Rhizinaceae. DuittRIcH’s investigations on the Geoglossaceae 
showed, contrary to the opinion formerly held, that these forms, 
in their young stages at least, were unmistakably angiocarpous. 
He discovered that the young fruiting body of Leotia was surrounded 
by an envelope of hyphal filaments, which later gelatinized, and was 
then disrupted by the expanding ascoma beneath. In Mitrula 
phalloides the phenomena were quite similar, but among the Hel- 
vellaceae which he examined there were no stages young enough to 
enable him to decide as to the presence or absence of an envelope. 
In Mitrula the ascogenous hyphae were found to originate from 
hyphae which were differentiated in the central part of the fruiting 
body. These hyphae are long, stain readily, and are closely massed, 
while their nuclei are large, with a prominent nucleolus and a thin 
chromatin thread. From these filaments the ascogenous hyphae 
grow toward the hymenial layer, where a rapid branching takes 
place, succeeded by the formation of asci. 
DvRAND (10), in his admirable monograph on the Geoglossaceae, 
makes reference to Dirrricn’s investigations on the envelope in 
Leotia and Mitrula, and remarks, “observations of my own on several 
different species, before I learned of Dirrricu’s work, point unmis- 
takably to the same conclusion.”” Duranp states that he found a 
veil in Mitrula phalloides, Microglossum viride, Cudonia lutea, and 
Spathularia velutipes, but “sections of quite young ascomata of 
Geoglossum glabrum, Gleoglossum difforme, and Trichoglossum velu- 
tipes have shown no traces of such a membrane.” Finally he affirms 
the belief that “when the development of the Discomycetes shall be 
195] [Botanical Gazette, vol. 49 
