July, 1922] BONNS A STUDY OF CLAVICEPS PURPUREA 
showed spore development in three weeks. A thick myceHal pellicle was 
obtained on nutrient solutions in 2}4 months. Aerial mycelium was pro- 
duced on bread, potato, and other organic media with inocula from previous 
cultures. Hyphae on solid media developed spores in scantier amount 
than those in water cultures. The great viability of the conidiospores 
was commented upon, and Meyer raises the question whether such spores 
may not winter over. No heliotropism was noted at any stage of growth. 
The plications on solid media noted by Brefeld were confirmed, together 
with the successive change in pellicle color from yellow to brown, but 
Meyer does not record the deep violet or purple stage which Brefeld em- 
phasizes. A resting period of the fungus was indicated by a complete 
cessation of vegetative activity in mid-December of cultures started in 
July. Renewed activity with continued increase of mycelial growth was 
observed after a two months' rest period. Cultures in the resting con- 
dition gave off, when opened, an odor of trimethylamine. 
An attempt was made to distinguish a morphological differentiation 
between growths on solid and on liquid media. In the former the myce- 
lium was characterized by compact parallel grouping of the hyphae in 
bundles, whereas in liquid cultures the mycelium branched profusely and 
grew in all directions. 
With respect to sclerotial formation or a tendency thereto, Meyer 
sustains Brefeld in finding no indications in this direction, even in cultures 
held for a year. The hyphal elements of the resting pellicle were not 
pseudo-parenchymatic, as are the cells in a cross section of a sclerotium, 
but were grouped as masses of short cells, rich in fat. On the older con- 
voluted pellicles a closely compacted parallel hyphal development was 
noted. From these strands, basidiospore-like elements with terminal spores 
developed at right angles. The resting stage is regarded as purely conidial 
or basidial. 
Experimental 
It was impossible to begin the study here reported with ascospores, 
as work was started in June, when viable sclerotia of the preceding year's 
formation were not available. The attempt was therefore made to secure 
a growth from sclerotia just forming on that season's rye crop. A few 
rye heads with fairly well developed but still immature sclerotia were 
obtained in Northern Indiana in June, 191 9. These were readily cut 
transversely with a sterilized razor, the tissue being firm but not hard. 
Discarding the exposed tissue, portions were removed under sterile con- 
ditions from the interior of the sclerotium and transferred to agar. 
The medium used in the preliminary work was 2 percent agar (showing 
a reaction of +15 Fuller's scale) with decoctions made from rye seed, 
rye screenings, and germinated rye. The tissue thus obtained was trans- 
ferred to Petri dishes. Transplants which showed no contamination at 
