16 
carpel, nature of the stylopodium, winging of the fruit, character 
of the seed-face, number of oil-tubes, and general habit. 
Thus genera are reached, and in a way that seems to express re- 
lationship as well as can be done in any lineal arrangement. Oc- 
casionally genera will be found grouped together which seem 
farther apart than is consistent with other groupings. This fol- 
lows from the fact that we are only dealing with North American 
plants, and the intermediate forms not being represented in our 
flora, it hardly seems necessary to multiply subdivisions. It will 
further be noted that the presentation of genera differs but little 
from that of Bentham & Hooker, the only radical change being in 
associating Hydrocotyle (Tribe I) with Erigenia (Tribe V), 
which we have done because of the remarkable lateral flattening 
of the fruit. 
Directions for collection and study.-— It is very evident 
that no Umbellifer is fit for determination unless it has mature 
fruit. That this cannot be too strongly insisted upon is shown by 
the immense amount of immature and hence well-nigh useless 
material that encumbers our herbaria. The great confusion in 
which the order has fallen has in no small degree arisen from the 
attempt to determine the relationships of these immature specimens. 
No such attempt should be made, for it v/ill be mere guess-work 
at the best. When mature fruit has been obtained, it is not safe to 
depend upon surface inspection. This is deceptive even in the 
matter of oil-tubes, and has led to confusion, and of course does 
not reach the inner structures which are fully as important. Nor 
can a section of the dried fruit be depended upon, for the import- 
ant chai'acters drawn from the seed-face are more or less disguised 
by the drying. The only sure method is as follows: Soften and 
soak the fruit until it has regained its original plumpness® and then 
make a series of thin cross-sections in the middle region of the 
fruit. Submitting such sections to an inch objective the required 
characters will be easily and clearly seen. 
3 This may be done in a moment or two in boiling- water, but it is far better to soak the 
fruit slowly in cold soft water, with a little potash if it is particularly hard, and in a day or 
two it will regain all its original plumpness gradually, without any of the violent action 
that is apt to come from boiling.. 
