I first saw the great snakeskin liverwort back in the spring of 2003 in my west 40. A few years ago while mapping seeps in the woods there I came across what was probably the original plant and several other large colonies growing in around seeps. The flora and geology of freshwater seeps is of particular interest to me.
The great snakeskin liverwort (Conocephalum conicum) is probably one of the easiest liverworts to recognize. Its shiny, dark green to yellow-green, large thallus, 16 to 20 mm wide and 12 to 25 cm long, with large coarsely hexagonal scales, each with a raised pore, across the surface are distinctive characteristics and easily observed. A line of two or three rows of parallel linear scales form a sort of mid-vein down the middle of the thallus. On either side of this row are scales diverging obliquely from the middle out to the edge. The thallus forks periodically giving the whole plant a branching appearance. The underside of the thallus is covered with numerous purple rhizoids that anchor it to soil and other moist substrates.
Having said that, in light of a new species delineation I now have reasons to doubt my original identification but the matter cannot be settled yet (see below “Another species of Conocephalum?“).
Habitat and Plant Communities
The great snakeskin liverwort is distributed across the northern hemisphere except in the extreme Arctic and grows in moist shaded places or sometimes full sun along creek banks, in seeps, and on moist rock outcrops where soil and water chemistry are mildly base-rich to neutral.
The specimen pictured above grows along the margins of and on high spots in a slow seepage that periodically dries up during the summer. It is located in mixed deciduous-coniferous forest composed of black ash (Fraxinus nigra), aspen (Populus tremuloides), red maple (Acer rubrum), yellow birch (Betula allegheniensis), white spruce (Picea glauca), beaked hazel (Corylus cornuta), mountain maple (Acer spicatum), and tag alder (Alnus rugosa). Associated bryophytes seen with it are Rhizomnium punctatum, Thuidium delicatum, and Climacium dendroidium. Associated vascular plants include golden saxifrage (Chrysosplenium americanum) and naked miterwort (Mitella nuda). Soils where the seeps are located are glacial outwash in origin with a fine sandy loam texture and contain quartz, feldspars and other alumino-silicate minerals from basalt, gabbro, slate, sandstone, graywacke, banded iron formation, gneiss, and granitic rocks. In general, the soils tend towards an acidic pH and are low in calcium carbonate but soil and water chemistry in seeps can be radically different from the surrounding upland soil.
While often eaten by slugs and snails liverworts, or for that matter mosses and lichens, are not usually thought of as host plants for moth and butterfly larva. In the case of the great snakeskin liverwort there is a group of small, primitive moths, the Micropterigidae, whose larva feed almost exclusively on it.
When the thallus of Conocephalum is gently rubbed between the fingers a fragrant mushroom odor is emitted. The odor is from volatile aromatic terpenoid compounds which are being investigated for potential medical uses.
Another species of Conocephalum?
Conocephalum conicum was for a long time thought to be the only species in the genus Conocephalum and the only member of its family Conocephalaceae. Recently, a new species has been identified and named Conocephalum salebrosum (Szweykowski et al. 2005). It differs from C. conicum on several characters. After reading Szweykowski et al. (2005) and Long (2010) it appears that C. conicum may be restricted to Europe while C. salebrosum is more widely distributed. So who knows? Perhaps the great snakeskin liverwort growing in the seeps in my western 40 are actually C. salebrosum. Then again it could be C. conicum. The answer to this will have to wait until April or May when the snow melts and ground thaws. Then I will be able to collect good specimens for inspection. When I find out I’ll post an update.
Next biodiversity post: Another lungwort lichen, Part 1
BBS Field Guide online pages
Long, D., 2010. Conocephalum conicum/salebrosum, Great Scented Liverwort/Snakewort in Mosses and Liverworts of Britain and Ireland – a field guide. Atherton, I., Bosanquet, S., and Lawley, M., editors. 2010. British Bryological Society 2010. Latimer Trend and Co. Ltd, Plymouth, England.
Schuster, Rudolf M. 1953. Boreal Hepaticae, A Manual of Liverworts of Minnesota and Adjacent Regions. The American Midland Naturalist (Vol. 49, No. 2, March 1953).
Szweykowski, J., Buczkowska, K., and Odrzykoski, I. J. Conocephalum salebrosum (Marchantiopsida, Conocephalaceae)- a new Holarctic liverwort species. Plant Systematics Evolution (Vol. 253, 133-158).