292 
The Ohio Naturalist. 
[Vol. XI, No. 5, 
Araceae of the northeastern United States are treated below for 
illustration. This synopsis is supposed to show both the natural 
relationships and the orderly arrangement, in series, of groups of 
lower and higher value. The key is simply a device for the easy 
recognition of the genera. The essential mark of a good key is 
that it makes use of such characters only as are present at a 
certain season of the year or a certain period of the life history. 
I. 
II. 
1 . 
1 . 
2 . 
2. 
3. 
3. 
4. 
4. 
5. 
o. 
SYNOPSIS. 
Flowers bisporangiate; plants without or with lactiferous cells. 
1. Without lactiferous cells; with a perianth.. Pothatae 
a. Without a typical spathe. 1. Acorus 
2. With lactiferous cells; with or without a perianth. .Cai.latae 
a. Without a typical spathe; with a perianth. . 2. Orontium 
b. With an open spathe; without a perianth; spadix 
elongated 3. Call a 
c. With an enveloping spathe; with a perianth; spadix 
globose 4. Spathyema 
Flowers monosporangiate; plants with lactiferous cells; without a 
perianth. 
1 . Spadix covered to the tip with flowers Philodendratae 
a. Flowers monecious; leaves simple o. Peltandra 
2. Spadix with a sterile projection at the tip Aratae 
a. Flowers monecious or diecious; leaves compound . 
6. Arisaema 
KEY. 
Inflorescence without an obvious spathe; flowers bisporangiate, with a 
perianth. 2. 
Inflorescence with a large, expanded spathe. 3. 
Spadix apparently lateral; scape 3-angled and grooved. Acorus. 
Spadix terminal; scape cylindrical. Orontium. 
Leaves compound; spadix with a prominent sterile projection at the 
tip. Arisaema. 
Leaves simple; spadix usually without a sterile projection at the tip. 4. 
Flowers monecious, on an elongated spadix; leaves prominently sagitate 
with rather distinct points. Peltandra. 
Flowers bisporangiate, on an oval or globose spadix; leaves cordate or 
only slightly sagitate. 5. 
Spathe open, with a slender point; spadix ovoid or somewhat elongated. 
Calla. 
Spathe enclosing the globose spadix; not with a slender point. Spathyema 
At present we do not possess the necessary morphological 
details to make a final classification, yet the broad outlines of a 
natural arrangement can be laid down with a fair degree of cer- 
tainty. When several parallel lines are to be grouped, one can, 
of course, use his individual judgment, the better plan probably 
being to follow expediency. If the methods and principles 
employed are correct there should not be much change in the gen- 
eral scheme, in the future, except in matters of detail. The 
larger problem of the correct limits of families and orders cannot, 
of course, be considered at present. It must be recognized, 
however, that some of the families, like Saxifragaceae, as formerly 
delimited, are mere waste-baskets to receive odds and ends which 
