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E. J. KRAUS 
woody tissue, the leaves are slender and light gray-green. Such plants are 
practically without the more complex reserve carbohydrates, and are high 
in moisture, in total nitrogen, and in nitrate nitrogen. 
Class II. When there is present an abundance of nitrogenous nutrients 
and available carbohydrates, both are utilized in vigorous vegetative exten- 
sion with little or no tendency toward sexual reproduction. The plants 
produce no sexual parts or a few frequently abnormal flowers or flower 
clusters which very often are partially transformed into leaves or stems, 
and very rarely set or mature fruit; they are exceedingly vigorous vegeta- 
tively, have stems of large diameter, soft and succulent with a small amount 
of woody tissue, and large, soft, and intensely dark green leaves. Such 
plants are relatively low in reserve carbohydrates but are higher than those 
of Class I, are high in moisture, in total nitrogen, and in nitrate nitrogen. 
Class III. When there is a limitation of the nitrogenous nutrients in 
relation to the available carbohydrates, so that the latter can accumulate 
in excess of their utilization in vegetative extension, then the plants become 
sexually reproductive as well as vegetatively active. The plants produce 
many good-sized blossoms, a large proportion of which set and mature; 
are less vigorously vegetative than those of Class II; the stems are of large 
diameter but firm to the touch and with considerable woody tissue; the 
leaves are large, and dark to light green in color. Such plants contain 
greater quantities of reserve carbohydrates than those of Class II, but are 
lower in moisture, in total nitrogen, and in nitrate nitrogen. 
Class IV. When there is a further relative reduction of the nitrogenous 
nutrients without inhibiting a possible increase of carbohydrates, there 
results a large accumulation of the latter, a decrease in vegetative activity 
and in sexual reproduction. Such plants produce few small-sized blossoms, 
a large proportion of which either fail to set and mature, or miature into 
small, tough fruits; they are feebly vegetative, the stems are of small 
diameter, very firm and hard to the touch with relatively much woody 
tissue; the leaves are small, stiff, and light green or yellowish in color. 
Such plants contain large quantities of the more complex carbohydrates, 
but are low in moisture and in total nitrogen and are almost completely 
lacking in nitrate nitrogen. 
Naturally these classes, depending as they do upon a quantitative 
relationship of various substances within the plant, blend insensibly into 
one another according as these relationships are varied, but what might be 
called the mid-points within them are very distinct. What departures 
from these groups may occur when either light or temperature is made a 
limiting factor can not be stated, but they can be duplicated in soil, sand, 
or water culture. The term nitrogenous nutrients is used because at the 
present time it is not definitely known what forms the effective nitrogen 
may have within various plants. In some, great vegetative extension is 
associated with nitrogen in the nitrate form. Of course it is not assumed 
