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Water
soluble anthocyanin and betacyanin
pigments also accumulate in the leaves in
late summer and fall. Anthocyanin is
rather common and red if the leaf moisture
is acid, which is what we see in
blueberries, some dwarf birch, dogwood and
fireweed (tall willow herb).
Betacyanins
are red but are found only in some plant
families. In Alaska, Chenopodiaceæ
(goose foot family) is our best example.
Some of the plants in that group have red
leaves in early spring, some all of the
time, and some when stressed or in
fall.
The
combinations of carotenes and xanthophylls
in birch, aspen and cottonwood can vary
from leaf to leaf, or from one tree to
another. This causes some of the trees
with bright yellow fall colors to vary in
shade and intensity.
The
fall leaves used as a header for this
article, are: Red - willow, nagoon berry,
dwarf birch, fireweed and dogwood. Yellow
- aspen, cottonwood, willow and paper
birch. Orange/yellow - shield fern,
shrubby birch and a leaflet of burnet. To
the right is and aspen
grove.
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End
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OBSERVATIONS
INDEX
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