Thursday, January 03, 2019

Fir twig blisters

In the duff beside Ridge Trail, a litter mostly composed of fir twigs, needles, Bigleaf maple leaves, scraps of lichen, I saw what at first glance seemed to be some leftover electronic detritus, human trash; two fragments of something like wires wrapped in bubbly tape. When I pulled away the leaves covering it (muttering to myself about careless hikers, even up here), it turned out to be a small fir branch, with weird bubbles at the tips.

(Sorry, anonymous hikers; my bad.)

The branch, on site. Bubbles and cups. The main terminal twig is 2 inches long.

I looked around and found no others. I brought this one home to examine more closely.

The bubbles grow out of the top and sides of the twigs. The bottom side is bare.

Each little bubble is about 5 mm. long, 3 mm across the top. They are hard and dry, with a faint resiny odor. I broke one off and tried to cut it in half; it crumbled, was still hard all the way through. With my hand microscope, I could see no structure, just random crumblies. Rubbing it between my fingers released a stronger resin scent..

Zooming in on a few bubbles.

Lower down on the branch, these pits (about 4 - 5 mm. across) seem to be the remains of previous bubbles.

A few dried needles remained on the branch. I examined these under the microscope. They are flat, with one centre vein, and a notched tip; their length varies from 1 to 1.5 cm. At the root, they have a half twist, then grow out straight. They're pale brown, as dried needles usually are, but are covered with blackish spots.

It seems that they are some sort of parasitic growth, probably a fungus, maybe one of the rusts. There is a similar disease, White Pine Blister Rust (Cronartium ribicola) that infects needles and bark of pine trees, but the blisters are not the same.

I need help here; can anyone identify these?

Another view. Sort of reminds me of octopus tentacles.

1 comment:

  1. I'm no help, but am always amazed at how you are so observant. I seem to walk around in a fog most of the time. - Margy


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