Sunday, September 4, 2016

The Weed du Jour

from a distance, it looks like someone shot
"Silly String" all over the weeds
Dodder (Cuscuta sp.) is a fairly well known group of parasitic plants that form iconic masses of yellow, leafless vines over their hosts. Dodder plants are aggressive and use root-like organs called haustoria to penetrate the stems of their hosts and siphon off their water and nutrients, often to the point of host-death. Given that dodder species have little to no chlorophyll with which to make their own nutrients, it is crucial for young seedlings to find a host before they run out of the energy supplied by their seeds (usually about 5-10 days).
Up close, you can see the little white flowers
It's pretty common here in the herbaceous plants along the road sides. I took these pictures a few days ago on a walk to the beach with Skye.
Studies have shown that these seedlings can use airborne volatile organic compounds to locate their host plants, almost like a plant-y sense of smell! Cuscuta seedlings can even detect which of their neighboring plants are more suitable hosts and will actively grow towards them. Once a young plant successfully reaches a host, its embryonic root rots away and it becomes wholly dependent on its parasitism. The fact that this plant can sense its hosts makes it a candidate for a creepy plant-horror film and earns it a place amongst its esteemed parasitic brethren.
Walk past fast. . .

Wikipedia informs us that they are related to Morning Glories (makes sense) and has common names such as "trangle tare, scaldweed, beggarweed, lady's laces, fireweed, wizard's net, devil's guts, devil's hair, devil's ringlet, goldthread, hailweed, hairweed, hellbine, love vine, pull-down, strangleweed, angel hair, and witch's hair."

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