“Ground Pine” Club Moss
In addition to the club mosses that resembled cedar leaves that I posted last week, we also found a lot of these plants that looked like tiny little pine or spruce trees on November 5, 2016 at the Churning Rapids Ski Trails:
Of course, these are no more pine or spruce trees, than the ones last week were cedar trees. These are also clubmosses, one of three very similar species that are commonly found in this area – Lycopodium obscurum, Lycopodium dendroideum, or Licopodium hickeyi.
The branches of these clubmosses tend to be dichotomous, that is, at each fork there are two branches (unlike actual pines, which tend to have multiple branches). They also don’t get very tall, all of the ones we saw were no more than about 6 inches tall.
The spore-bearing heads are at the tip of stalks that don’t look much different from the other branches, aside from not branching as much.
The individual spore heads are only about an inch long.
After they emit their spores, the stalk stays green and presumably keep growing.
Anyway, the bulk of these plants is an underground rhizome, sending up periodic shoots and seed heads. So, when we found “patches” of these, they were most likely all one plant and not a bunch of individual plants.
In our climate, I think these are basically “evergreen” plants, with the green parts overwintering under the snow. I believe that they produce spores in the spring, at least I think that is the time of year I remember walking through them and kicking up clouds of spores. They may not be limited to a particular time of year, though, because spores are not pollen. See, when flowering plants release pollen, they have a timing issue. The pollen grains have to be released at the same time as flowers are ready to receive them, and so most flowering plants have a very specific time window when they will bloom. Club mosses (and other spore-producing plants) don’t need to do that. They can release spores any time. Their only constraint is that they want to pick a time when conditions might be suitable for the spores to take hold and start growing. Which could be any time of the year, regardless of what the other club mosses in their species might be doing. For practical reasons, they would prefer times when it is sufficiently moist for the spores to start growing, but not so moist that the water will make the spores clump up and never become airborne. Optimum times in our climate would therefore generally be either late spring, or early autumn.
Even with good timing relative to the weather, though, there is a very low probability of any given spore actually taking root and growing successfully, because it has no reserves and needs everything to be just about perfect for some period of time. As opposed to seeds, which can be formed any time and then just wait around until conditions are right for sprouting, and use their reserves to get through any brief periods of dryness or other inclement conditions. Which is why (a) spore producing plants produce such ridiculous quantities of spores, and (b) flowering plants are generally more successful at spreading their seeds than spore-bearing plants like club mosses.
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Great summary of spores vs pollen. I had never considered this. Thanks!