Many plants are iconic to the Pacific Northwest, at least in the minds of those who live here. Around Western Washington, Sword Fern, Salal, and Western Hemlock are well known and well represented at the Bloedel Reserve. In Eastern Washington we recognize Ponderosa Pine and Sagebrush. Those of you transplanted to Washington may recognize other hallmark plants from your point of origin. Such plants are facets of the places we know as “home”.
One group of plants we all recognize though is mosses. They are the green, cushiony carpets of our forests and the drapery on our trees. But they occur not only in wet areas but in almost all terrestrial environments. In Eastern Washington where I grew up, there is moss out in the hot sand, hidden under the sparse shade of Sagebrush, dormant in the blazing summer to awaken with the autumn rains. Even the ice-free areas of Antarctica sport mosses. One of them, Ceratodon purpureus, incidentally, is the same species you and I clean off our roofs. But even if we do not know what species they are, we do know they are mosses.
Upon finding a moss, however, greater than 99% of us will have no idea what species we are looking at. They are a cryptic plant group that is daunting even for many botanists to identify, joining the ranks of grasses, sedges, and willows. But, as any botanist will also tell you, learning to identify the more difficult plant groups is not impossible. It just takes patience. Sometimes a lot of patience. And perhaps a little magnification in the form of a good hand lens. Learning a few of the easier mosses is a good place to start.
The next time you visit the Moss Garden at Bloedel Reserve, look for these six mosses listed below. They are among the easier mosses to identify. Treat it as a botanical treasure hunt.
Bent Leaf Moss
This moss is quite possibly the easiest moss in our area to identify and many of you probably have it in your yards at home. In fact, it’s a common lawn moss in our area. Most of the ground moss along the sunnier parts of the paved road in front of the Moss Garden is Bent Leaf Moss. This species gets its common name because each leaf is “bent” 45 degrees downward (a useful recognition clue).
What to look for:
- Grows on the ground, especially in yards and disturbed areas. Likely to be found in the sunnier parts of your garden than in full shade.
- Light green to yellowish-green color.
- When viewed from above, its vertical growing stems look like stars (figure 1).
Figure 1. Bent Leaf Moss. Note the “starry” appearance when viewed from above.
Figure 2. Bent Leaf Moss growth habit.
Figure 3. Large patch of Bent Leaf Moss in the northwest corner of the Moss Garden.
Menzies’ Tree Moss
Oh, this is a tree moss? It must grow on trees, right? Nope. It is called a tree moss for a reason, but you need to get on your hands and knees to see why. Look for it on the ground. When you think you’ve found a patch of it, push the individual plantlets apart to see them better. If you’ve found Menzies’ Tree Moss, each plantlet will look like a miniature tree. For the majority of mosses in our region, this habit is unusual. Only Climacium dendroides, simply called “Tree Moss” has a similar habit, but so far is unknown at the Bloedel Reserve.
What to look for:
- Grows on the ground in shadier spots than Bent Leaf Moss.
- Light green color.
- Tree-like growth habit of individual plantlets where the main stem branches heavily near the top.
Figure 4. Menzies’ Tree Moss plantlet displaying its “tree” like growth habit.
Figure 5. Close up of a Menzies’ Tree Moss patch. The “whiskers” are immature sporophytes (spore producing structures). They are not always present.
Figure 6. A patch of Menzies’ Tree Moss.
Juniper Haircap Moss
If you’ve ever taken a botany or biology class and learned even a little about mosses, you’ve probably seen pictures or even specimens of this moss. Moss life cycle diagrams frequently depict this species, probably with good reason: this species grows on every continent, even Antarctica.
There are several look-alikes for this moss. Some are other species of Polytrichum. Others are related species of Pogonatum and Polytrichastrum. Pogonatum contortum is very common in the Moss Garden but can be distinguished from Juniper Haircap Moss by its lack of reddish-brown awns at the ends of its leaves.
What to look for:
- Bluish-green, un-branched, upright plants.
- Each leaf ends in a reddish-brown awn (a narrow, bristle point). This can usually be seen with the naked eye, but magnification is helpful.
Figure 7. Juniper Haircap Moss.
Figure 8. Note the reddish-brown awns on the leaf tips of Juniper Haircap Moss.
Figure 9. Juniper Haircap Moss.
If you pay much attention to the scientific names here, you’ll notice that this moss belongs to the same genus as Bent Leaf Moss listed above. They are related and somewhat similar. Both occur commonly on the ground though Lanky Moss will more often be seen on logs or stumps. Both are also often dominant ground covers and tolerate some sun well, but Lanky Moss seems to tolerate shade better than Bent Leaf Moss.
A third species of Rhytidiadelphus¸ R. triquetrus (Goose-necked Moss), is in the Moss Garden too. It is distinct from its two sister species but is much less common.
What to look for:
- Yellowish green, usually with reddish color in the stems.
- Lacks the “starry” look of its sister, Bent Leaf Moss.
- Irregularly branched.
- Leaves of the main stem spreading, not pressed against the stem as in the look-alike Spear Moss.
Figure 10. A mat of Lanky Moss.
Figure 11. Close up of Lanky Moss stem, showing spreading leaves
Figure 12. Lanky Moss stem. Note the irregular branching habit.
I am not sure exactly which species of Dicranum is growing in our moss garden. Possibly there are more than one residing species. With about 20 species in the Pacific Northwest, they can be difficult to tell apart, but I wanted to include it here simply because it stands in the Moss Garden enough to attract the attention of the occasional moss hunter.
What to look for:
- Bright green leaves. Much brighter than the surrounding species such that this moss really stands out visually.
- The leaves are curved to one side (see figure 14). This trait is not unique to Dicranum, but if you find curved leaves on a bright green moss, you’ve probably found the Dicranum in the Moss Garden.
Forms smallish clumps on logs or humus. This species does not seem to form large, dominant mats in the Moss Garden.
Figure 14. Close up of Dicranum showing curved leaves.
Figure 15. The Dicranum in the Moss Garden is noticeable by its bright green color against the darker or more yellowish mosses.
Spear Moss resembles Lanky Moss and the two can be hard to tell apart. To make things worse, they both grow in similar habitats (on the ground, often in yards, although Lanky Moss is more common in natural habitats). In some places in the Moss Garden they can even be found growing intermixed. Despite the similarities though, they can be distinguished if you know what to look for.
What to look for:
- Growing on the ground or less commonly on stumps or logs.
- Leaves pressed close to the reddish main stem, not spreading. Leaves on the lateral stems (usually not reddish) tend to spread more. This differs from Lanky Moss that has spreading leaves on the main stem.
- The main stem has a spear-like appearance (hence the common name). To see this, look at the pictures below and imagine the main, reddish stems without their lateral branches. The growing tip of the main stem appears as the spearhead, so to speak.
Figure 16. Spear Moss. Note the yellowish color. The main stems can have a reddish color to them like Lanky Moss.
Figure 17. Overall habit of a Spear Moss stem.
Figure 18. Two Spear Moss stems.
Print out this article, grab your magnifier, take them with you to the Moss Garden at the Bloedel Reserve, and look for these mosses. When you think you’ve found one, spend some time looking at it. Develop a mental image. You may find that learning to identify a moss is not so much about special features and habits, but more about textures and color shades. That is how you will remember the moss the next time you encounter it. Not that you shouldn’t learn the features that distinguish the species; they are what helped you learn the mosses. With this, you will also learn that studying mosses takes patience. Often that is more important than a magnifier.
If you think you want to continue learning mosses, these are three books I’d recommend:
- Kimmerer, Robin W. 2003. Gathering Moss: A Natural and Cultural History of Mosses. Oregon State University Press.
- Pojar, J. and A. MacKinnon. 1994. Plants of the Pacific Northwest Coast. Lone Pine Publishing.
- Vitt, D.H., et al. 1988. Mosses, Lichens, and Ferns of Northwest North America. Lone Pine Publishing.
The last two are for identification. The one by Pojar and Mackinnon is especially good, not just for learning mosses, but other local native plants as well. Gathering Moss is an outstanding introduction to the world of mosses written for everyone to read regardless of level of familiarity with mosses. It’s not really about identification, but if you liked mosses before reading it, you will love them afterwards. You will never look at them the same.
—Written by Darren Strenge
Darren Strenge is the Plant Health Manager for the Bloedel Reserve where he has worked since the late 1990s, managing irrigation, plant pathology, the Reserve’s First Detector Program, and various other garden jobs. Prior to that he was a researcher in the plant sciences and holds a Bachelor of Science in Horticulture and a Master of Science in Botany. Darren has a broad range of botanical interests but has a soft spot for the “underdog” plants: mosses, ferns, lycophytes, and others sitting in the shadow of the showy flowering plants.