Today, I want to take a look at some of the very small among plants: mosses. They may be often overlooked, or even maligned, but appreciated when we get to lie down in a soft bed of moss in off-the-beaten-path forest.
Botanically, mosses are non-vascular plants in the land plant division Bryophyta. They are small (a few centimeters tall) herbaceous (non-woody) plants that absorb water and nutrients mainly through their leaves and harvest carbon dioxide and sunlight to create food by photosynthesis. They differ from vascular plants in lacking water-bearing xylem tracheids or vessels. As in liverwort and hornworts, the haploid gametophyte generation is the dominant phase of the life cycle. This contrasts with the pattern in all vascular plants (seed plants and pteridophytes), where the diploid sporophyte generation is dominant. Mosses reproduce using spores, not seeds and have no flowers.
Mosses are small flowerless plants that typically grow in dense green clumps or mats, often in damp or shady locations. The individual plants are usually composed of simple, one-cell thick leaves, attached to a stem that may be branched or unbranched and has only a limited role in conducting water and nutrients. Although some species have vascular tissue this is generally poorly developed and structurally different from similar tissue found in other plants. They do not have seeds and after fertilisation develop sporophytes (unbranched stalks topped with single capsules containing spores). They are typically 0.2–10 cm (0.1–3.9 in) tall, though some species are much larger, like Dawsonia, the tallest moss in the world, which can grow to 50 cm (20 in) in height.
Mosses are commonly confused with lichens, hornworts, and liverworts. Lichens may superficially look like mosses, and have common names that include the word “moss” (e.g., “reindeer moss” or “iceland moss”), but are not related to mosses. Mosses, hornworts, and liverworts are collectively called “bryophytes”. Bryophytes share the property of having the haploid gametophyte generation as the dominant phase of the life cycle. This contrasts with the pattern in all “vascular” plants (seed plants and pteridophytes), where the diploid sporophyte generation is dominant.
Mosses are in the phylum (division) Bryophyta, which formerly also included hornworts and liverworts. These other two groups of bryophytes are now placed in their own divisions. There are approximately 12,000 species of moss classified in the Bryophyta.
The main commercial significance of mosses is as the main constituent of peat (mostly the genus Sphagnum), although they are also used for decorative purposes, such as in gardens and in the florist trade. Traditional uses of mosses included as insulation and for the ability to absorb liquids up to 20 times their weight.
This image was captured about 10 years ago in Baxter StateForest in Maine using a Canon EOS 1D Mk III and EF 70-200mm f/2.8L lens. Exposure settings were 1/60 second at f/6.3 at 400 ISO.