4th JANUARY 2014
PRAEGER CENTRE, NATIONAL BOTANIC GARDENS
LEADER: KATY DUFF
BOGS, MOSSES AND LIVERWORTS
Katy introduced us to members of the Sphagnum genus some of which are essential components of peat bogs. 34 species are known from Britain and Ireland but quite a significant number are limited in their occurrence having either a northern or western distribution. Others have become relatively scarce in Ireland as a result of the destruction of our raised bogs.
species, as non-vascular plants, have the ability to absorb water directly into
their cells and have the resilience to quickly rehydrate after dry weather.
a simple key and hand lens (x20) we were shown how it was possible after some
experience to separate Sphagnum species ‘in the field’ into Sections: Sphagnum,
and then to identify the species using further characteristics. Important
characteristics are the shape of branch and stem leaves. For example, members of
the Section Sphagnum
have a conspicuous stem cortex with thickness one third of stem radius.
Ultimately some species will require microscopic examination for confirmation.
species on display included S. fallax, S. austinii, S. fuscum, S.
tenella, S. magellanicum, S. papillosum, S. palustre and S. capillifolium.
palustre Blunt-leaved Bog-moss (Sphagnum): Is rather variable in colour,
forming large, untidy mats or loose hummocks which are green to yellow-brown.
Characteristic are the swollen branches which are blunt-tipped because of the
crowded concave branch leaves with their hooded tips. It may be found in
moderately enriched sites, for example in wet woodland, ditches, stream margins
papillosum Papillose Bog-moss (Sphagnum): Forms mats and low hummocks and is
generally pale ochre-brown. It never has a trace of red. The capitulum of centre
and spreading branches are always similar in colour. Upper spreading branches
are short and blunt-tipped….
Found in raised and blanket bogs it can be confused with S. magellanicum
and S. palustre in certain circumstances.
squarrosum Spiky Bog-moss (Squarrosa): Is usually bright green and spikey
looking. Branch leaves are abruptly pointed and tapering with a tubular tip
curved away from the branch.
denticulatum Cow-horn Bog-moss (Subsecunda): Plants are green yellow-brown
to dull coppery red. The outer capitulum branches are swollen and smooth in
outline and the leaves have flat edges. Some of the branches are curved, with
the leaves towards the tip appressed to each other tightly appressed to each
other resembling a cow’s horn …..
capillifolium Acute-leaved/Red Bog-moss (Acutifolia) : It is a
hummock-former and is pale-green under heather and stem branches are usually
‘chaotic’ in structure. Erect stem leaves are triangular in shape. This
species is often separated into subspecies capillifoium and rubellum.
fallax Flat-topped Bog-moss (Cuspidata) : This species was at one time
considered to consist of a larger number which are now amalgamated..It is a
medium-sized green to mustard-brown growing in carpets. Capitula are convex and
usually stellate with developing branches in neat pairs apparent between the
capitula rays …. It is very common in wet habitats including nutrient poor
fens and pools and runnels on bog and may be found with Soft Rush Juncus
After lunch, participants presented a wide variety of bryophyte specimens for identification. These included a number of Sphagnum species, two of which were not on display during the morning session namely, S. subnitens a member of the Acutifolia Section that can resemble S. capillifolium, and S. cuspidatum, which grows in bog pools, whose appearance has been likened to a “drowned kitten”.
number of other bryophytes were also identified:
a thread-like liverwort with round leaves, was present in many of the Sphagnum
samples examined. It is one of the commonest liverworts found on hummocks of Sphagnum.
glaucum forms characteristic whitish mounds that are found under heather, or on
burned bogs where they are more visible.
occurs on bogs and heaths. It has tall, robust shoots, and toothed leaves. It is
much larger than other Polytrichum species.
is a delicate fern-like, bipinnate moss. It resembles and grows in similar
habitats to Thuidium tamariscinum. It differs from the latter by having a
red rather than a green stem.
is a very conspicuous bushy plant of calcareous woodland, in contrast to Rhytidiadelphus
squarrosus, whose shoots have a starry appearance and which is ubiquitous in
lawns and in unimproved grassland.
Mosses and Liverworts of Britain and Ireland a field guide. British Bryological Society Edited by Ian Atherton, Sam Bosanquet & Mark Lawley (2010).
Mosses and Liverworts E.V. Watson. Cambridge University Press (1981).
Note: This publication has good microscopic illustrations but
nomenclature is now out-of-date for some species.
Pat Lenihan & David Nash
S. papillosum S. squarrosum S. palustre
S. subnitens S. squarrosum S. cuspidatum
S. magellanicum S. capillifolium sssp. rubellum S. fallax
Polytrichum commune Rhytidiadelphus squarrosus Rhytidiadelphus triquetrus
Hylocomium splendens Leucobyrum glaucum
Photographs © P Lenihan
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