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I'Hfi AMEftlCAK BOTANIST. 
Odor of Hound's-tongue. — It may be questfonecl 
whether all flowers have not an appreciable odor to the 
insects that x^sit them. We are inclined to assume that 
because certain flowers have no odors that are perceptible 
to us, they have no odors perceptible to other members of 
creation. It frequently happens, however, that flowers* 
we have set down as odorless are really not so, our mis- 
take arising from the fact that perfume from single flowers 
is too faint to be perceived by our senses. In such cases,, 
one may often detect the odor by picking a bunch and 
smelling of them in the mass. The hound's-tongue (Cj220- 
glossum officinale) w^ell illustrates this. There are few 
individuals with senses keen enough to notice the odor of 
single blossoms, but in a bunch the flowers have a strong, 
musky, mouse-like odor. This is apparently well liked by 
the bees for during the season of bloom it attracts great 
numbers ol these insects. 
Change of Color in Flowers.— The changes in color 
which many flowers undergo during the time they are in 
bloom are so striking as to be well known. Among these 
may be mentioned the change of the white wake-robin 
(Trillium grandiflorum) from white to pink, the change of 
the blue-bell (Mertensia Virginica) from pink buds to deep 
blue flowers and the honeysuckle from white to yellow. 
Many less conspicuous changes in flowers are fully as 
interesting if we take the trouble to look them up. Many 
of these changes are concerned w^ith the honey guides and 
are doubtless of service to visiting insects by indicating to 
them the age of the flower. A striking example of this is 
found in the horse-chestnut which Gray says — incorrectly 
—has a white corolla spotted with yellow and purple. As 
a matter of fact the petals each have a single spot at the 
base. The flower opens with these spots pale lemon- 
yellow, but they change rapidly to orange, then brick red, 
and end by being of a deep purple, not the purple of grapes 
and lilacs, but the purple in which there is a blood-red 
tint. Another instance may be found in so common a 
plant as the toad flax (Linaria vulgaris) in which the pale 
