Reaching through the thorny bramble, my fingers closed on the biggest,
juiciest, blackberry I had ever seen. My pail was over half full, but this
berry did not join the crowd, instead I popped it straight into my mouth. Sweet
juice burst into every corner of my mouth. Yum!
I love berry season!
Berry season is a
time for red fingers and purple tongues.
Not just blackberries, but raspberries, serviceberries, and blueberries
all contain a pigment called anthocyanin, which can be red, purple, or blue
depending on the acidity of the fruit.
In nature, pigments do not just provide color; they also carry out
important functions. Anthocyanin is
useful to plants as a sunscreen, and to us as an antioxidant.
In fact, blackberries’ antioxidant capacity ranks near the top of 1000
antioxidant foods consumed in the United States. They are also notable for
their high nutritional contents of dietary fiber, vitamin C, vitamin K, folic
acid (a B vitamin), and the essential mineral manganese. Blackberries even
retain most of these health benefits through the process of making them into
jam and storing them over the winter.
As my pail filled
with blackberries (the goal of the day), my mouth often filled with red
raspberries, too. These close cousins share the genus Rubus in the Rose Family. Have you ever noticed that when you pluck
a raspberry off the plant, there is a little white dome left behind? The
matching recess in the berry itself is the perfect size for capping little
fingertips, or hiding sneaky bugs. Blackberries do not have that. Their base is flat, and they pluck cleanly
off the stem. There is a botanical reason for this.
Raspberries and
blackberries begin with very similar flowers. They both have five white petals
that surround an outer ring of many stamens (the pollen-producing part) and an
inner cluster of pistils (the female part). All these parts are joined at the
base in a structure that botanists call the hypanthium.
The hypanthium, in turn, is attached to a flower stalk called the receptacle.
As a pollen grain lands on one of the many stigmas (the tip of the pistil),
it travels down a pollen tube to fertilize the ovule (egg) in the ovary. The
fertilized ovule becomes the seed, and the ovary develops into the juicy fruit.
On raspberries, the top parts of the pistils remain as tiny hairs bristling out
of each bump on the fruit.
Have you ever noticed how hard blackberry seeds are when they get stuck in
your teeth? Each tiny seed is enclosed in a lignified (woody) case – just like
the pit of a peach. The term for this type of a fruit is a “drupe.” Cherries
are another good example of drupes.
As the many pistils in raspberry or blackberry flowers receive pollen, each
ovary develops into a little drupe or “drupelet.” The drupelets then fuse together into the
many-dimpled raspberry we know and love. Thus, blackberries and raspberries are
not berries at all, but “aggregates of drupelets.” True berries are simple (not
aggregate) fruits that develop from a single ovary. Some examples of berries
include avocados, bananas, blueberries, grapes, tomatoes, watermelons, and
pumpkins.
The main difference between the two fruits I encountered in the thorny
bramble is that in addition to fusing all the little drupes together,
blackberries incorporate the receptacle (the base of the flower) into the
fruit, while raspberries leave their little white cone of a receptacle still
attached to the plant.
While botany fascinates me, at the end of the day, the only receptacles
that I pay attention to are the full pail and my happy belly!
For
over 44 years, the Museum has served as a guide and mentor to generations of
visitors and residents interested in learning to better appreciate and care for
the extraordinary natural resources of the region. The Museum invites you to
visit its facility in Cable at 13470 County Highway M. The new exhibit, STAR POWER:
Energy from the Sun, opened in May 2012 and will remain open until April, 2013.
Find us on the web at www.cablemuseum.org
to learn more about our exhibits and programs. Discover us on Facebook, or at
our blogspot, http://cablemuseumnaturalconnections.blogspot.com/
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