Grimmia ovalis (tentative) and Niphotrichum ericoides (tentative)

A lot of thank-yous are in order for today’s entry. First of all, thank you to Wouter Bleeker of the Geological Survey of Canada for sending me today’s images via email. Wouter is responsible for the first two photographs, and his friend Mike Stubley is the photographer of the third. Also, thank-yous to local bryologists Terry McIntosh (speaker at next week’s Cedar Series Lecture) and Steve Joya for their attempts to identify these mosses without having samples in hand (identifying mosses from photographs is nearly impossible without a lot of close-up images). I’ll add one more thank-you in the last paragraph of this entry as well.

Since the identifications are tentative, today’s entry will instead be about the phenomenon shown in the images, on which Wouter wrote:

“For my field work I am up in the (sub)Arctic quite a bit, and here I attach some pictures of an interesting plant phenomenon: mobile moss or what we jokingly call “galloping moss”. These mosses are slowly creeping downhill, probably by daily frost-thaw cycles in spring and fall, and they seem perfectly happy with the movement. I have seen it in different moss species, including Sphagnum (not shown). Sometimes they stall out at a little crack or ridge, like in the first photo, only to start moving again after a while. If the hill side steepens, their leading edges may be overrun by the rest and things get a little messy, but otherwise all is fine. Some other species sometimes seem to catch a ride, as a small Saxifraga species in the second picture (upper right).”

“The most interesting aspect, perhaps, is that they leave this time-dependent trail from where they came, with the surface just vacated, bleached in the sun for 1-2 years or so, nice and clean; further back other algae and lichens slowly start growing back again. I don’t know the duration to full recolonization of the rock surface but this could be figured out and calibrated. It is probably on the order of 10-20 years. Just by coincidence, in the first two pictures the moss carpets are growing on stromatolitic limestone, formed by 1.9 billion year old cyanobacterial mats on a shallow, warmish, seafloor. These rocks are now exposed on the East Arm of Great Slave Lake, NWT. The third photo is from further north in the barren lands.”

Assuming the species identifications are correct, a few links: Grimmia ovalis (oval dry rock moss) and Niphotrichum ericoides in the Flora of North America, Niphotrichum ericoides (includes close-up photo) via the Natural History of Southeast Alaska, and Grimmia ovalis (with photographs) from the USDA PLANTS database.

On a different topic (and a different thank-you): my gratitude to Edmund Seow, Computer Systems Manager in the Faculty of Land and Food Systems here at UBC, for helping return Botany Photo of the Day (and the rest of the BG web site) back to normal. I think all issues are now resolved, and even though things will be changing again in April with the redesign of the entire UBC BG site, a problem-free web site for the next two months will be a huge relief.

Grimmia ovalis (tentative)
Grimmia ovalis (tentative)
Niphotrichum ericoides (tentative)

29 responses to “Grimmia ovalis (tentative) and Niphotrichum ericoides (tentative)”

  1. Daniel Mosquin

    Terry McIntosh also sent along a comment that another (and perhaps more likely) possibility for the moss species in the third photograph is Racomitrium lanuginosum.

  2. Virge Lorents

    Re: Grimmia ovalis (tentative) and Niphotrichum ericoides (tentative), is there an explanation for the streak left behind the moss? A chemical reaction to a secretion?

  3. Old Ari

    You should have kept these pics until April 1st.

  4. Bonnie

    Too cool! And are many of them heart-shaped?

  5. Transplant

    I’m fairly sure I’ve seen this as far south as the North Cascades in Washington State, if I recall correctly on a north-sloping outcropping in a narrow valley that would have some pretty big temperature swings between direct sunlight and shade, that might go along with frost-thaw cycle theory.
    Re: Virge Lorents – I assumed it was because the moss kind of “cleans” the rock surface by preventing the growth of other organisms. I’d guess a lot of the dark color of the rock is from the growth of algae & lichen, and from minerals left by run-off from above the bare rock – the moss would kill whatever’s living in it’s path (sounds so dramatic when put that way!) and shield the rock from from the effects of run-off and weatherization.

  6. Steven Romero

    Nature is a very wonderful and mysterious thing! Thanks for sharing!

  7. phillip

    …A rolling moss gathers no stone..?

  8. Connie

    I see ID is tentative- are you sure they’re not Tribbles?

  9. Donald DeLano

    No, a rolling moss gathers a Saxifraga… and I agree, or maybe a Halloween release for the ‘Attack of the Galloping Moss’. Really a great article, as always.

  10. b moro

    Nature confronts us again with the astounding. Galloping moss – a truly great name. The speed of the gallop is something to behold…

  11. Lisa Haglund

    Galloping moss is the perfect description: they look like little buffalo surging down a slope from afar, with a trail of dust behind them (especially in the first image). Great photos, and fascinating write up, thank you.

  12. Alice Jordon

    Love the galloping moss! Wonder if it secretes an acid (like lichens do) that breaks down the surface of the rock leaving the trail.

  13. canaryfish

    Perhaps I’m stating the obvious, but I thought that I would ask because it’s not specifically mentioned in the article… are the mosses not only “cleaning” the rock, but actually metabolizing organisms that they stampede over to better survive in the very trying conditions of their environment? Other than the moss clumps, the other organisms on the rock seem to be very small in comparison. Perhaps the mosses have gained an advantage by becoming mobile and “consuming” all of the organisms downhill? Not just killing them by accident? The moss could be getting stuck on the cracks, but also, there are likely more nutrients in the cracks because they would catch debris washed down the surface of the rock. Maybe they stay longer there for that reason. That’s not to suggest that they’re consciously making decisions lol – but given the pressures of the environment, selection could favour mosses that did this kind of thing.. right?? Or am I kooky? 🙂

  14. Irma in Sweden


  15. wendy

    Well if Canaryfish has it right they would then be the Galloping-Grazing Moss.

  16. Amy

    Similar images have been captured of rocks ‘racing’ in death valley.

  17. elizabeth a airhart

    are we all sure botaday did not turn into the syfy channel
    happy trails to you

  18. Basia

    These wonderful galloping mosses deserve a time-lapse or stop-motion animation video – preferably set to the finale of the William Tell Overture!

  19. Eric Simpson

    What a truly bizarre and wonderful phenomenon!

  20. Patrick Williston

    On glaciers, these vagrant mosses are called jokla mys, or glacier mice.
    Rolling mosses (carrying small stones) are also known from gently sloping, cryoturbated soils of British Columbia. Great herds of them roam the alpine around Smithers.

  21. Sally

    This one made my day!! Now I really have seen everything! Thanks for telling us about the galloping mosses. (I like “glacier mice” too; great name.)

  22. Daniel Mosquin

    Here’s a follow-up photograph from Allan Green of New Zealand taken of Racomitrium lanuginosum in Tierra del Fuego, with the moss having a similar effect but creeping upwards on the rock.

  23. elizabeth a airhart

    i think one would use the galloping mosses to round up
    all those herds of rolling mosses– indiana jones would

  24. Doby Green

    Moss is important in nature as one in a series of plants that form soil. First, often, is the algae-fungi symbiotic plant that attaches itself to rock and by the chemical action gets a hold there and grows, forming a holding structure for the moss that is next able to attach and survive with the first growing organisms. With its forming of acid, that breaks down the rock particles so that the first bits of soil are forming and making a bed for the next plants that can get a grip on the sparse soil matter, through it and the particles, fern is able to grow there and put up a taller organism to withstand the air movement and water movement and yet hold together the particles of a mat of soil, held together by
    roots or rhizomes that function as roots can. The lighter trails of where there was so little soil and some erosion, the chemical action erodes some of the soil
    particles along with the gravity pull or however the plant is meeting its forces.
    After the growth of ferns, and along with that, is the potential of enough soil to
    allow the grasses and other herbaceous plants to get a grip and grow and add humus
    to the mass to continue growth into the more complex plants that may then grow there, if the water, sun, and temperature range allow the ones that can adapt to
    that biosphere.

  25. Jim Borland

    Whose job is it to return the moss cushions to the top of the rocks?

  26. Barbara Mompo

    Fascinating- as I live in PR, I’m quite curious about these mosses growing in the tropics? I suppose you wouldn’t be able to locate these streaks, if they existed, since everything else grows so quickly here. Comments?

  27. Wendelyn Duke

    As I was viewing the photos, I couldn’t help wonder whether the mosses perhaps have a unique growing pattern (as opposed to actually moving). Has anyone looked at the mosses closely enough to see whether new growth is limited to the area on the “leading edge” of the so-called-movement? This may be due to prevailing wind patterns at that location. The “trailing” edge of the moss may in fact be caused by the moss’ dying due to depleted nutrients on the substrate directly beneath it. Thus, a section of the moss doesn’t move; but, instead dies once the nutrients directly under it are depleted. J

  28. canaryfish

    Interesting Wendelyn Duke! I think that you might expect a “C” shaped pattern if growth occurs on the leading edge and death on the trailing edge.. it sure looks like that is happening in the follow-up photo posted by Daniel Mosquin of Racomitrium lanuginosum in New Zealand. But the clumps of Grimmia ovalis and Niphotrichum ericoides at least superficially look to be a lot more uniform in shape! I wonder why there’s a difference. And it’s super interesting that the Racomitrium appears to be moving uphill. There must be a reason why – in this case, it can’t be attributed to gravity… Maybe the difference could be the whole uphill thing. For the mosses moving downhill, the trailing edge still receives nutrients that are washed down the face of the rock with any precipitation or melt water (in addition to nutrients beneath the moss body). For the mosses moving uphill, the trailing edge is located on a nutrient-deficient surface, and it also likely receives less nutrients washing downhill because the leading edge is absorbing anything before it gets to the trailing edge. But.. all of this is just speculation! I wonder if this is something that could be researched.. it would be hard to design experiments on mosses that take decades to move! 🙂

  29. John B.

    Rather than freeze/thaw cycles causing this, I would suggest it’s caused by expansion & contraction as the mosses get wet or dry out.
    BTW are you sure the mosses aren’t actually eating the lichens as they crawl over them??? This isn’t as facetious as it sounds–if they are killing the lichens by shading them out, they are surely benefiting from the nutrients being released as the lichens die.

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