Guide to Liverworts of Oregon: Scapania undulata (L.) Dum.
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Scapania 1 oil bodies several per cell > Scapania 2b marginal teeth evenly spaced or lacking > Scapania 3b dorsal lobe not decurrent > Scapania 5 ventral lobe long decurrent > Scapania 6b dorsal lobe 2/3 of ventral lobe > Scapania 7b dorsal lobe round > Scapania undulata
Synonym: None.
Special Status: None.
Recognition: The non-decurrent dorsal lobe coupled with a long-decurrent ventral lobe and aquatic or amphibious habitat are characteristic of the species. The dorsal lobe often will be slightly decurrent by a narrow line of cells below the point of insertion. However, the dorsal lobe is abrubtly narrowed to this insertion point in contrast to species which are decurrent by a gradually narrowed wing extending down the stem. The variation from finely dentate to completely entire leaf margins can be confusing; note that the perianths of this species are always dentate even if the leaf margins are entire.
Distribution: On various substrates, invariably near water; at all elevations, widespread in the state. Especially abundant on rocks in flood zone of streams; occasionally completely submerged year around. Frequent.
Comments: A distinctive species occurs in our area which grows on mineral soil away from the typical streamside habitats of Scapania undulata. Based on a close correspondence with the original description, I treat this species as Scapania oakesii Aust. In most recent literature this name has been referred to as a subspecific taxon of Scapania undulata. If this taxonomic interpretation proves correct when the type of Scapania oakesii is re-examined, our local species will probably need a new name. I do not believe it is conspecific with Scapania undulata.
Scapania undulata Shows non-decurrent dorsal lobes. Opal Creek, Marion County, Oregon. DHW m2143.
Shoot showing insertion of dorsal lobe. Marys Peak, Benton Co., Oregon. DHW m1636
Shoot showing insertion of ventral lobe. Marys Peak, Benton Co., Oregon. DHW m1636.
Leaf cells showing oilbodies. Left: Lane Co., Oregon. DHW 7626. Right: Mesa Creek branch, Lane County, Oregon. DHW m1772b.
Scapania undulata Bigelow Lakes, Josephine Co., Oregon. DHW m2873. Dorsal aspect. A specimen mimicking S. subalpina.
Scapania undulata Bigelow Lakes, Josephine Co., Oregon. DHW m2873. Dorsal aspect.
Scapania undulata. Left: oil bodies in showing cell walls natural color. Right: oil body count in modified image. Washburn Beach, Lane County, Oregon. DHW m2933.