Jungermannia pumila
| Common Name | Dwarf Flapwort |
| Frequency | Infrequent |
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Distinguishing Features
Presenting on siliceous rocks along rivers and creeks, this inconspicuous pale-to-dark green simple leafy liverwort is loosely appressed to its substrate and spends significant portions of its year submerged in flowing water. The simple, spreading ovate leaves occur on irregularly-branched shoots up to 2mm wide undergirded by a tangle of dense, colourless rhizoids. Underleaves are lacking, but developing archegonia and antheridia are frequent and can be found on different parts of the same plant (“monoicous”). The modified leaves that surround the archegonia (“perianth”) form a characteristic ovoid sheath with a plicate or ribbed apex (see photo).
Similar species
This is a very generic looking liverwort, but it can be distinguished from other similar species by its habitat, lack of underleaves, rhizoids and reproductive characters. Relatively few species of liverworts have unlobed, simple leaves AND live the semi-aquatic, rock-bound life that J. pumila partakes in. Of those, species of Nardia, Chiloscyphus and Odontoschisma have obvious underleaves that can be seen with a hand lens. The remaining lookalikes are all within the group of taxa that have at one time or another been part of the genus Jungermannia. Jungermannia exsertifolia is restricted to subalpine drainage banks and has equidimensional leaves on shoots that are 2.5 mm or wider, whereas shoots of J. pumila are less than 2 mm wide and bear leaves that are longer than they are wide. Plectocolea obovata and P. hattoriana are also found on siliceous rocks in streams, but both have bright red-purple rhizoids, whereas those of J. pumila are colourless. Solenostoma confertissimum is very similar in size and habitat, but its leaves are about as wide as they are long, whereas J. pumila has leaves that are longer than wide. Jungermannia atrovirens is identical in size, shape and semiaquatic lifestyle, but it grows on calcareous rocks and has antheridia and archegonia on separate plants.
Habitat
Moist to wet, often shady mineral soil, rock outcrops, cliffs, ledges, crevices, boulders, fens, and streambanks in the lowland and montane zones
Associated species
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Distribution Map
Relevant Literature
- Godfrey, J.D. (1977). Hepaticae and Anthocerotae of southwestern British Columbia . [Doctoral dissertation, University of British Columbia]. UBC cIRcle.
- Hong, W. S. (2007). Scapania. In Flora of North America Editorial Committee (Eds.), Flora of North America North of Mexico (Vol. 3) . Oxford University Press.
- Wagner, D. H. (2013). Guide to the liverworts of Oregon: Scapania undulata . Oregon State University Herbarium.