FIELDBOOK OF ILLINOIS WILD FLOWERS 
on a waste area of sandy soil, we find a little plant with a slender 
stem, ordinary net-veined leaves, smooth ovary and blue corolla. 
Each flower has § narrow sepals, but the petals are grown to- 
gether into a labiate and spurred corolla. There are 4 stamens 
and 1 pistil. Perhaps if we look about a bit we will notice one 
or more plants like ours having fruits, for we may need these 
in the process of identification. 
We begin again with number 1 in the key, go to Ig, 20, 22, 
23 and 24 as we did before, since as yet the same characteristes 
belong to this plant as to the other. At 24 we diverge, however, 
since our second plant has united petals. At 53, to which we 
have been directed, we choose “‘Calyx free from the ovary” 
and go to 54, which, because the corolla is conspicuously irregu- 
lar, sends us to 65. Here the smooth ovary determines that we 
must go to 66, and now we must turn to the fruits. These are 
not reflexed on the stem, consequently we pass to 67, and because 
we have already seen that our flower is neither heart shaped nor 
2-spurred, we go to 68. Here the many seeds in the capsule 
settle the question: our plant is in the Figwort family. 
Now when we turn to page 299 as provided, we find that 
this large family contains several genera for which a key had 
to be provided also. In this Key to Genera will be found the 
Latin or Greek names only. Using this key exactly like the first, 
the genus to which our plant belongs will soon be discovered, 
and after that there will be only one or two full-length descrip- 
tions to choose from to establish the species.* 
Under 1 in the Key to Genera, we choose between “Herbs” 
and “Trees,” and then going to 2, between “Perfect stamens 2,” 
“Perfect stamens 4,” and “Perfect stamens 5.” The stamens 
have anthers and filaments and so are perfect, and since there 
are 4 of them we proceed to number 3. Here we find “Corolla 
spurred at the base,” and “Corolla not spurred,” and since the 
corolla is spurred it must belong to the genus Linaria. This 
genus is represented by two species, beginning on page 301, of 
which the second, or blue toadflax, Linaria canadensis, page 
302, is the one that fits this plant. 
*It should be remembered that all the keys have been constructed 
for the particular purpose of running down the plants which this 
book describes, instead of the families and genera at large. 
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