Tag Archives: symbiotic

Green slime mold

Plasmodial slime molds (class Myxogastria) come in many colors (yellow, purple, orange, blue, red), but rarely in green, so this find at a local park intrigued me. I found it February 23 under the bark of a decaying pine tree in Springfield, Pennsylvania. There were no fruiting bodies. 

I’m curious what species it is (let me know, if you know, please), but would love to know why it’s green. Here are three possibilities (I have more, if they fail): (1) the slime mold has formed an association with an algae or cyanobacteria, (2) the green pigment replaces the yellow pigment under some conditions, and (3) this is a species of slime mold that’s green but not frequently encountered so not part of books and online keys. The latter two are most likely, but the first was interesting to consider … see below if you have a few minutes.

Colin Purrington Photography: Slime molds &emdash; Green slime mold

(1) In regards to algal associations, I looked into this option first because the green appeared so exactly like that of alga. Of course, I’d never, ever heard of algal/myxomycetes symbiosis, so I looked into this possibility very, very quietly so people wouldn’t spew coffee out their noses. But I eventually found an article on the topic (Lazo, W. 1961.Growth of green algae with Myxomycete plasmodia. American Midland Naturalist 65:381-383). Here’s the summary from his abstract:

“Three species of Chlorella were able to enter into full associations with Physarum didermoides and Fuligo cinerea, forming green plasmodia in which the algae multiplied in light.”

The above association was under special laboratory circumstances, however, notably using slime molds that he’d purged of their bacterial partners with antibacterials. But even though the conditions might seem artificial, I suspect slime molds have a built-in ability to purge themselves (and surrounding substrate) of bacteria. And algae are easily found growing in soil and on dead trees, so it’s very likely that slime molds and algae come into contact in the wild regularly. And algae (or at least some species like Chlorella) can grow heterotrophically in the dark (e.g., on sucrose) and still remain green. This latter fact is important because I found this slime mold under rather thick bark, and I doubt it received any appreciable light. 

Indeed, some plasmodial slime molds appear to even specialize on the algal biofilms growing on wood (reviewed in Smith 2007). One mentioned by Smith is Barbeyella minutissima, which I Googled and found this:

“In addition to liverworts, Barbeyella is found socialised with monocellular algae. It is assumed that the protoplasmodium phagocytizes either the algae or the bacteria on their surface.”  — Global Fungal Red List Initiative

Smith also mentions that a Didymium iridis plasmodium harbored an alga (Trebouxia sp.) for months in a laboratory culture (Keller and Braun 1999; I couldn’t obtain to read).

So if the above scenario does occur, perhaps it’s similar to the trick noticed in some Dictyostelium spp. (cellular slime molds, in the class Dictyostelia), which known to carry around bacteria, which they can release onto substrates that are favorable for bacteria (i.e., they farm). 

Anyway, I don’t have a microscope to examine the slime mold for algae or cyanobacteria, so the above is just mere speculation. I suppose I could spray it with a good herbicide, but that’s seems cruel.

(2) The green color might simply be a pigment change. I don’t know much about myxogastrid pigments, but apparently moisture, light, starvation and other environmental factors all cause color changes. But I could find only a few papers discussing a green pigment. Here’s the best line from one of them:

“The yellow pigment of P. polycephalum has been found to be an excellent natural pH indicator (Seifriz & Zetzmann, 1935). In a neutral medium, the natural indicator is yellow, in an alkaline medium it is bright green, and in an acid medium it is deep reddish orange.” Seifriz and Russell (1936) [emphasis added]

[The citation of the referenced paper, which I couldn’t obtain in full, is Seifriz, W., and M. Zetsmann. 1935. A slime mould pigment as indicator of acidity. Protoplasma 23:175-179.]

The above fact is really interesting, but don’t know why a decaying pine log would become alkaline. I couldn’t find any good research on the topic, but perhaps I missed it.

The more interesting scenario is that a pigment gene is mutated. Mutations happen, though it’s rare enough that I don’t think it’s likely. 

(3) It’s of course most likely that there’s a species of green slime mold and I’m simply ignorant of its existence. Maybe it’s not even a slime mold.

(4) Or it could be oobleck


Some more pics:

Colin Purrington Photography: Slime molds &emdash; Green slime mold plasmodia

Colin Purrington Photography: Slime molds &emdash; Green slime mold

 

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Stalked puffball-in-aspic (Calostoma cinnabarinum)

Here’s a gooey, mysterious find from my trip to Mohonk Mountain House over Thanksgiving. It took me a while to identify, but I think it’s a stalked puffball-in-aspic (Calostoma cinnabarinum), an ectomycorrhizal boletes that is associated with oak tree roots. It has a number of amusing common names such as hot lips and pretty lips. This one was growing around a pine tree, so perhaps they are flexible about their symbiotic partner. It’s also possible that roots from distant oaks extended to this location (there are some leaves in the frame). But I think the former is more likely, partly because I found a paper (Bautista-Nava and Moreno-Fuentes 2009) that says they grow in pine forests in Mexico. But that paper is in Spanish, which I cannot read, so I could have that wrong.

 Colin Purrington Photography: Fungi &emdash; Stalked puffball-in-aspic (Calostoma cinnabarinum)

After reading they were puffballs, I of course had to hike back to the site to confirm that. Sure enough, filled with spores.

Colin Purrington Photography: Fungi &emdash; Stalked puffball-in-aspic (Calostoma cinnabarinum) spores

I’d love to know whether the smaller blobs (most visible in the first photograph) have some supporting function. They apparently are part of the spore case and fall off as the fruiting body matures. But do they also mature into mini puffballs, too? If they don’t, I wonder whether they might act as egg mimics to attract vertebrates (squirrels? raccoons? birds?) that would then step on the larger fruiting bodies, releasing spores. Likely not, but I’m risking the speculation because they look exactly like fish or amphibian eggs, and most guides mention this similarity. In really weak support of this idea, some guide books say it is especially common near streams (where frogs, salamanders, and fish might be common). For those laughing hysterically at me, I would like to mention in my defense that fungi have evolved to mimic termite eggs on several occasions (Matsuura and Yashiro 2010), so it’s not completely without precedent. OK, you can keep laughing now.

Here is a trio of fruiting bodies approximately a foot or so away from the above location. They are in the process of emerging from the soil. The egg-like pieces are still attached underneath, I believe. Would be nice to capture the emergence and maturation on time-lapse.

 Colin Purrington Photography: Fungi &emdash; Stalked puffball-in-aspic (Calostoma cinnabarinum)

If you can share any natural history on this species, I’d love to know more. Please leave a comment or email me.

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