Family HYLOCOMIACEAE

Common name

LANKY MOSS

Microhabitat

This moss is often the dominant ground cover in humid lowland and montane temperate rainforests in coastal BC such as Stanley Park. We found this species infrequently along Tatlow Trail growing on soil and occasionally on the base of vine maple trees (Acer circinatum) often away from the trail. This moss can also be found growing on rocks and decaying logs.

Distribution

Rhytidiadelphus loreus is widespread along both coasts of North America as well as Europe, generally in lowland and mountain forests. It is found on the east coast of Canada from the Maritimes to Newfoundland. In the west, R. loreus is predominantly found in the coastal mountains and more rarely on some of the inland mountain ranges to the Rockies.

Close-up of leaves
Photo Credit: Yan Zhuang

Click on thumbnails to view photos

Morphology

Plants are yellow-green and large with single pinnate branching and branches widely spaced with some tapering to fine points. Shoots overlap to form loosely woven mats. Stems are red-brown so the moss often appears tinged with red. Leaves are slightly falcate (curved at the tip) and have very distinct pleats. They can be secund (all pointing in one direction) or irregularly spreading, but they are never squarrose (bent back to protrude at right angles from the stem). Individual leaves are 3.5-4.0 mm long, broadly egg-shaped at the base, and gradually tapered to a long, slender point. Paraphyllia (long, green filaments) are not present on the stems.

As with other species in this family, sporophytes are uncommon, but when present, they originate from the side of the stem. They are red-brown and have hard, glossy, subspherical capsules that are inclined when mature.

Key identifying features

The curved and pleated leaves, red-brown stems, and regular branching are all distinguishing features. The bright green tips of growth in spring make this moss appear decorated. R. loreus is quite straightforward to distinguish from the other feather mosses that make up this family. The species is overall less rough and bristly looking compared to R. triquetrus. It has pleated, non-squarrose leaves while R. squarrosus has squarrose leaves that are not pleated. R. squarrosus is generally found in more open sites. Also, mats of R. loreus have single pinnate branching versus Hylocomium splendens which has double pinnate branching. R. loreus is much larger than Eurhynchium species.

Interesting notes

This species forms wonderful thick green carpets on the floor of coastal western hemlock (Tsuga heterophylla) forests. Its beauty and abundance make it a preferred species of the craft industry. It is frequently “harvested” as a non-timber forest product from local forests to be used for decorative purposes, such as lining hanging baskets and as part of shop window displays.

The name of this genus means "brother of Rhytidium" and refers to its close resemblance to the genus Rhytidium. The specific epithet means “striped”, referring to its striped appearance given by the pleats on the leaves.

Tissue from this species was recently studied to investigate the nutrient contribution of salmon carcasses deposited onto the forest floor by grizzly bears and other predators and scavengers along streams in coastal old-growth forests. Nitrogen derived from the fish leave a different signature than other available forms of nitrogen. Data suggest that the salmon-derived nutrients make an important contribution to non-vascular plants of the riparian zone of old-growth forests throughout the Pacific Rim.

This moss has also been found to be adversely affected by clearcut logging, disappearing entirely from some harvested sites. It also appears sensitive to disturbance along Tatlow Trail as it was only found at minimally disturbed sites away from the trail.

Selected References

Pojar, J., and MacKinnon, A. 1994. Plants of Coastal British Columbia. BC Ministry of Forests and Lone Pine Publishing, Vancouver, Canada.

Wilkinson, C.E., Hocking, M.D., and Reimchen, T.E. 2005. Uptake of salmon-derived nitrogen by mosses and liverworts in coastal British Columbia. Oikos 108: 85-98.

Schofield, W.B. 1992. Some common mosses of British Columbia, 2nd ed. Royal British Columbia Museum, Victoria, Canada.

Vitt, D.H., Marsh, J.E., and Bovey, R.B. 1988. Mosses, Lichens & Ferns of Northwest North America. Lone Pine Publishing, Edmonton, Canada.

By Patrick Lilley

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© 2006 Department of Botany, University of British Columbia