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. 



SYNOPSIS. 



I. Flowers bisporangiate; plants without or with lactiferous cells. 



1. Without lactiferous cells; with a perianth Pothatae 



a. Without a typical spathe 1. Acorns 



2. With lactiferous cells; with or without a perianth C.\llatae 



a. Without a typical spathe; with a perianth. , . .2. Oronlium 



b. With an open spathe; without a perianth; spadix 



elongated 3. Calla 



c. With an enveloping spathe; with a perianth; spadix 



globose 4. Spathyema 



II. Flowers monosporangiate; plants with lactiferous cells; without a 



perianth. 



1. Spadix covered to the tip with flowers Philodexdratae 



a. Flowers monecious; leaves simple 5. Peltandra 



2. Spadix with a sterile projection at the tip Aratae 



a. Flowers monecious or diecious; leaves compound. 



6. Arisaema 

 KEY. 



1. Inflorescence without an obvious spathe; flowers bisporangiate, with a 

 perianth. 2. 



1. Inflorescence with a large, expanded spathe. 3. 



2. Spadix apparently lateral; scape 3-angled and grooved. Acorns. 



2. Spadix terminal; scape cylindrical. Orontium. 



3. Leaves compound; spadix with a prominent sterile projection at the 



tip. Arisaema. 



3. Leaves simple; spadix usually without a sterile projection at the tip. 4. 



4. Flowers monecious, on an elongated spadix; leaves prominently sagitate 



with rather distinct points. Peltandra. 



4. Flowers bisporangiate, on an oval or globose spadix; leaves cordate or 



only slightly sagitate. 5. 



5. Spathe open, with a slender point; .spadix ovoid or somewhat elongated. 



Calla. 

 5. 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 fonnerly 

 delimited, are mere waste-baskets to receive odds and ends which 



