Guide to Liverworts of Oregon: Marsupella brevissima (Dumort.) Grolle
HOME SPECIES INDEX GENUS INDEX GLOSSARY
Marsupella 1a plants paroicous > Marsupella 2b oil bodies 2-3 per cell > Marsupella 3b dark green to reddish-brown > Marsupella 4b perianth vestigial > Marsupella brevissima
Synonym: Gymnomitrion brevissimum (Dumort.) Warnstorf
Special Status: None.
Recognition: This is a tiny, dark, brownish green liverwort with bilobed leaves that grows on cliffs, rocks and pebbles in the high Cascades. Leaf cells have mostly two oil bodies but always a few cells have three oil bodies, unlike other small species of the genus which have strictly only two. Identification is based on finding traces of antheridia in bracts subtending a capsule bearing shoot tip.
The perianth is not well developed, the archegonia mostly enclosed by bracts.The presence of a shoot calyptra is distinctive for this species (Paton 1999). A shoot calyptra is a cylindrical projection of the tip of the shoot that bears archegonia. It can be recognized by the old, sterile archegonia on its side. It is interior to the perianth or perigynium when such is present. This is not at all easy to demonstrate. Photos here show analysis of a typical dissection of a young gynoecium from a rehydrated herbarium specimen.
P>Distribution: On rock, from cliffs to pebbles. An arctic-boreal species that extends down the crest of the Cascades. Likely to turn up also in the Wallowa Mountains on acidic rock.Comments: Rare enough to be considered for sensitive species status but its montane habitats have not been thoroughly explored. Probably will be found to be stable and widespread in the high Cascades.
One of the two putative records of Marsupella adusta (as Gymnomitrion adustum) attributed to North America by Mamontov (2020), is from Mt. Hood in Oregon. Mamontov says that the specimens he studied are most closely related to Marsupella brevissima, with the main difference that separates them being oval leaves in Marsupella brevissima and more oblong leaves in the Oregon material. Molecular analysis and photomicrography of the specimens is worth pursuing.
Marsupella brevissima, Three Sisters Wilderness, Lane Co., Oregon. DHW 2603.
Marsupella brevissima, Three Sisters Wilderness, Lane Co., Oregon. DHW 2603.
Marsupella brevissima Perianth, maximal development; Mt. Ashland, Jackson Co., Oregon. DHW 2573b.
Marsupella brevissima Shoot calyptra; Mt. Ashland, Jackson Co., Oregon. DHW 2573b.
Marsupella brevissima Antheridia in bract from below gynoecium; Mt. Ashland, Jackson Co., Oregon. DHW 2573b.
Marsupella brevissima Antheridium; Mt. Ashland, Jackson Co., Oregon. DHW 2573b.