CONCERNING NOMENCLATURE. 299 
frond.” From the groups under this division marked d 
the one with roundish sori is selected and the division 
under it, with reniform indusium, shows his plant to be 
an Asfidium. Had the indusium been hood-shaped it 
would have been Cystopteris, if star-shaped, Woodsia, and 
soon. A simple magnifier costing from fifty cents to 
one dollar willbe found exceedingly useful in making out 
the nature of the indusium and in examining other mi- 
nute parts of the ferns. 
The majority of our fern genera contain so few species 
that keys to them would be quite superfluous. For the 
larger genera, Keys have been given by which the species 
may be traced, just-as the genera are in the large Key. 
Few who get really interested in ferns can resist the 
temptation to make an herbarium. Upon this point the 
author’s papers on “The Making of an Herbarium” may 
be consulted with advantage. To the student of ferns 
the herbarium is indispensable. It gives him material 
for study at times when it cannot be procured afield, and 
remain’ as a permanent record of much that would be 
lost if merely entrusted to the memory. In collecting 
for the herbarium or the’ fern garden, care should be 
taken not to carry away all of any rare species. Noone 
is held in greater contempt by the true student than the 
vandal who ruthlessly destroys a station for a rare plant. 
It is well to remember the old rule “ Of a little, take a 
little, and leave a little.” 
