337 
IL. Material and methods. 
Through the courtesy of Dr. H. L. Lyon, Dr. D.H. Camp- 
bell came into the possession of valuable material of both 
prothallia and various developmental stages of B. obliquum 
of the ‘“Ternatum” group; B. simplex; B. neglectum of the 
Subgenus Eubotrychium; and of B. virginianum of the “Os- 
mundopteris” group. AIl apparently preserved in 96% al- 
cohol. The material was collected several years ago in Minne- 
sota. In addition a nature plant of B. silaeifoluim, collected 
in California, was investigated. Of this plant the root structure, 
petiole and development of the stelar structures in the bud were 
studied. Eight young plants of each of the other four species 
were sectioned. By means of the paraffine method, sections 
of 10 y. were obtained. Following a suggestion of Dr. Campbell 
1% aqueous Bismarck brown (Vesuvin) was used as a stain 
for 15—20 minutes after which the sections were counter- 
stained with 1% alcoholic safranin during 10 minutes. This 
method has many advantages for anatomical work. It is very 
persistent and especially adapted for microphotographical work. 
The following number of plants were sectioned : 
Brobliquant ee + On MONS 
Bsinplet rt M Ce MS plants 
Ééneslecinmane © M 1 NS plants 
Étoramanmenate. ee NB plants 
BSlactoltmna uns CNE SAN Mplants. 
The petiole of B. lanuginosum was also sectioned. 
IL Botrychium obliquum. 
The development of this remarkable form was, until recently, 
very incompletely known. The work of Lyon (24) showed that 
its embryology differed very much from that of other Botrychia. 
