After the last post's exploration of the springtails and other delights to be found by closely examining mosses, last week brought a crazy eruption in some of the mosses growing in the gravel Lehman Ave. extension near the Sycamore Apartments.
Goblet mosses, or urn mosses (tentatively Physcomitrium pyriforme), are fairly subtle for most of the year, but when they are ready to release their spores in the spring, they produce bladderlike capsules atop thin stalks that are a little more eye-catching (relatively, as mosses go, I suppose). Like other mosses, their lifecycle is quite different from what we might imagine based on most of the plants we encounter.*
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| A cluster of balloon-like sporophytes. |
Mosses are non-vascular, non-flowering plants that have two basic life phases:
- Gametophyte generation. This is what we normally picture when we imagine moss: the plain, low-growing mats of tiny leaves. It is a haploid generation** that will produce shoots bearing either an archegonium that contains eggs or an antheridium that produces sperm. Water, via rainfall or other methods, can help the sperm make its way to an awaiting egg. Once fertilized, the moss will transition to its
- Sporophyte generation. This diploid generation is names after its sporophyte, the structure that carries and later releases its haploid spores to the world, which will grow into a new gametophyte generation and start the process all over again.
The balloonlike capsules here are the sporophytes, held up by the stalk, technically called the seta. The cup-like capsule has a lid (the operculum) that will fall away and allow the spores to disperse.
While we eagerly await the spring flowers and shows reproductive organs, it's a neat reminder that there are many other reproductive strategies in the world of plants.
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| Threadlike setae hold the sporophytes aloft. |
*Did I resort to searching "moss lifecycle for dummies" in researching this? Yes I did.
** If you remember high school biology, haploid refers a cell or organism with just a single set of chromosomes. Our gametes—reproductive cells like sperm and egg—are haploid, each containing a single set of the chromosomes that combine into a diploid cell with two complete sets of chromosomes.
Resources/Additional Reading:
- Urn Moss (Goblet Moss). Missouri Department of Conservation.
- Goblet Moss. Illinois Wildflowers.
