1886.] BOTANICAL GAZETTE. 139 
The inflorescence of the paniculate-flowered species should be illustrated 
when possible by samples showing the habit just previous to and following the 
period of bloom. In some species the panicle is expanded only for a very 
short time (during the period of actual bloom), following which the branches 
quickly become erect or appressed. Upon the adherence of the flowering 
glume or palea to the grain important characters are based, and it is scarcely 
necessary to add that ripe seed form a part of a good herbarium specimen. 
Grasses may be fastened to the sheets of the herbarium either with glue or 
strips of gummed paper. The latter method is especially suited to the peculiar 
habit of grasses, and even when fastened with glue the strips should be applied 
to the stems and stiffer parts, or they will quickly break away from the paper 
in handling.—F, L. Scrrpner. 
Aquatic Prants (NAIADACE®, EtC.).—The Potamogetons will serve as a 
type for dealing with all other aquatic plants. My plan is to collect speci- 
are of great importance, submerged leaves in good condition and mature fruit. 
Submerged leaves are at their best when the plant is young, or a little previous 
to flowering. In some of the species they can not be obtained at all in anthesis, 
as they decay and drop off before reaching that state, and in all the species 
they become more or less imperfect by the time the fruit matures. Mature 
fruit is absolutely necessary in order to identify some of the species. 
instance, P. pectinatus and P. marinus can be distinguished with certainty 
only by the fruit. The same is true of P. pauciflorus and P. Hillii; while in 
the case of P. hybridus and P. Spirillus both fruit and submerged leaves are 
It is also well to remember that a number of the species may or ma 
not develop floating leaves. Of the thirteen species found in North America 
twelve have this peculiarity. Floating leaves, however, are not a typical 
characteristic in this genus. Prof. Tuckerman long ago observed that “the 
Potamogetons are typically submersed plants, and their floating leaves become 
of importance in characterizing the species only when taken in connection with 
the submersed ones.” Whether such leaves are present or not will depend 
upon the depth of the water and the temperature of the season; and collectors 
must not suppose that they have discovered a new species because the floating 
leaves described in the books are absent, or because they appear on forms to 
which they are not attributed. I should not be much surprised to find floating 
leaves upon abnormal forms of any of the two groups which Dr. Robbins has 
named “ Conformifolii” and “ Angustifolii.” 
e drying of specimens is a very simple matter. All the specimens 
should be kept wet until placed between driers. After lying upon the table for 
a few moments to clear from dripping water, they should be laid separately be- 
tween thick pads of drying paper. Common newspapers or coarse wrapping pa- 
per will answer the purpose very well, if sheets enough are placed between the 
specimens. y a very moderate pressure should be applied, ten or twelve 
pound weights laid upon a pile ten or twelve inches high being quite enough. 
After being subjected to this pressure for two or three hours the driers should 
be changed entirely, even to the two sheets next to the specimens. This is th 
