1912] The Ottawa Naturalist. 161 



Chelsea. This was the more noteworthy in view of the fact 

 that Prof. Macoun's collection includes material from a number 

 of places in the neighbourhood. Failure to find it in a season 

 so favourable in many ways as the last may perhaps be ascribed 

 to the periodicity which some species seem to show in the years 

 of their appearance. The following are the sources of Prof. 

 Macoun's material: Beechwood Cemetery, Rideau Park, Rock- 

 cliffe, near Hull, Carleton Place. 



Fuligo ovata (Schaeff.) Macbr. F. septica (L) Gmel. 

 Though not abundant as regards number of individuals, speci- 

 mens were gathered in most of the localities examined, viz., 

 Chelsea, King's Mt., Rockcliffe, Blueberry Point, and several 

 places near the Exp. Farm. The largest aethalium gathered 

 measured about 4 in. by H, the smallest less than a fourth of 

 an inch in length. 



Physarum sinuosum (Bull). Weinm. on dead leaves and moss 

 near Hull (M) ; Exp. Farm. 



Physarum nefroideum Rost. King's Mt. 



Crater ium minutum (Leers) Fries C. pedunculatum Trent. 

 On dead Cedar twigs, Dow's Swamp (M). 



Crater ium leucocephalum (Pers.) Ditm. On a dead frond 

 of Pteris aquilina, Exp. Farm. 



Spumaria alba (Bull.) D. C. Mucilago spongiosa (Leyss.) 

 Morgan. Plasmodia of this species were met with in great 

 quantity amongst dead leaves in Beaver Meadow, in June. A 

 little later the aethalia were found attached to various neigh- 

 bouring objects, some on twigs on the ground, some on the 

 stems of grasses and branches of shrubs a foot or more above the 

 level of the ground. None of the aethalia were very large, the 

 largest measuring a little less than two inches bv one inch. 

 Aethalia were also obtained later in the season near the Exp. 

 Farm. 



Didymium squamulosum (A. & S.) Fries. On grass, dead 

 leaves, bark, etc. Beaver Meadow and Exp. Farm. A gather- 

 ing of this species made on June 9th was the first material col- 

 lected in properly matured condition. 



Diderma effusum (Schw.) Morgan. Gathered once near the 

 Exp. Farm on the leaves and petioles of a living plant of Mitella 

 diphylla. The fructification was chiefly on the lower surface 

 of the leaves, the chalky reticulations of the plasmodiocarp 

 showing a tendency to follow the projecting ribs of the leaf, 

 and also to envelop the stiff hairs occurring on both surfaces, 

 thus giving a peculiar lime-splashed appearance to the Mitella 

 plant. 



Diderma reticulatum (Rost.) Morg. Chondrioderm reti- 



