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IOWA ACADEMY OP SCIENCE 
conclusions reached; and a few cases of abnormal development sug- 
gested new morphological interpretations. 
In all, eighteen members of the family Araceae have been studied in 
the laboratory. In some cases the history has been worked out with 
substantial completeness. In others, it was impossible to obtain material 
in all stages of development, and a study has been made of certain 
isolated phases in the life history of the plant. In all cases the results 
are of soma morphologicaj significance. Aside from the difficulty of 
obtaining material in all stages of development, serious difficulties were 
encountered in handling the plants in the laboratory. Most members 
of this family contain a more or less tenacious gum or mucilage. These 
substances vary in the different species. Some of the gums are soluble 
in water (as in the case of Arisaema and Eichardia), some are insoluble 
in water but soluble in alcohol (as in Philodendron Wendlandii) and 
some are quite insoluble in either liquid. In most cases thei gum- ab- 
sorbs water readily and when placed in an aqueous fixing medium swells 
into a thin tenaceous jelly, distorting the tissues and ruining the prepara- 
tion. Acorns calamus proved especially troublesome in this respect. A 
saturated solution of corrosive sublimate in absolute alcohol dissolved 
the gum in most species, but is a poor fixing agent on account of the 
distortion of the tissues. Acorns proved refractory even to this reagent, 
and the results, in the case of that species, were poor. The mucilage of 
Hornalomena argentea dissolves in one per cent acetic acid, but better yet 
in acetic alcohol. Other species show varying reactions indicating in- 
dividual differences in the nature of the mucilaginous substance. In 
spite of these and other difficulties, good results, of definite significance, 
have been obtained and, in part, published in the Botanical Gazette for 
the years 1907, 1908, and 1913. 
While engaged in the morphological work above described, the -writer 
became interested in the Phylogeny of the primitive Monocotyledons — in- 
cluding, of course, the Araceae — and for his own satisfaction began 
attempting to work out a rational genetic classification, based in part 
upon our existing knowledge of the Anatomy of the Arales and his own 
study of Aroid Morphology. The latter thus was built into, and became 
a part of, a larger and more extensive scheme. Although in the pres- 
ent state of Botanical knowledge we cannot speak with dogmatic as- 
surance regarding the descent and affinities of this or any other family; 
nevertheless the evidence of Anatomy and Morphology is now sufficiently 
complete that some more or less definite conclusions can be drawn there- 
from. The writer has been led to question some existing theories re- 
garding the affinities of the Monocotyledons, and will here present some 
