Dodder
The southern
half of the Loop Trail is truly red in tooth and claw, full of murder and chemical warfare.
As you return to the parking area, you will pass by one more
bloodthirsty species, this one a native plant.
The
yellowish-orange vines of dodder are easily mistaken for a mass of
fishing line --- they clearly do not appear to be a plant. As you
probably learned in elementary school science, plants are green and
feed themselves by turning energy from the sun into sugars through
photosynthesis. Dodder does not do any of that. Instead,
dodder twines around nearby plants and sends modified branches, called
haustoria, into the support plants’ stems. The haustoria suck
nutrient-filled sap out of the host plants, feeding the parasitic
dodder.
Not every plant
is a suitable host for the dodder, though. Scientists are not
quite sure what makes a host plant tasty or disgusting to the twining
dodder, but they do know that dodder can tell the difference.
After making an initial loop or two, the dodder decides to either send
haustoria into the support plant or just grow a longer tendril,
reaching out toward a more tasty specimen. A recent study by Penn
State researchers suggests that dodder reacts to airborne chemicals
when determining the suitability of a host plant --- in essence,
smelling its prey.
In our area,
dodder is most often found in moist habitats where it seems to thrive
on hosts including jewelweed and Clearweed. Dodder can also be an
agricultural pest, choking crops such as potatoes. In my own
garden, I have a terrible time keeping the dodder off my carrots ---
once it catches hold of one carrot leaf, the dodder branches off in
several directions to penetrate every nearby plant. After a week
or so, the result is a tangled mass of dodder covering a few choked
carrot plants. Despite the devastation, I cannot help being
intrigued by this parasite that acts nothing like a conventional plant.
Not
pictured:
Dodder
Scientific
Name: Cuscuta sp.
Family:
Cuscutaceae (Dodder Family)
Habitat:
Moist, open areas
Blooms:
June to October
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