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THE
MOUNTAINS: The spray cliffs community
Spray cliffs
The spray cliff is
a distinctive community that has appeal for the naturalist because it
is always associated with waterfalls. Since accessing some of these communities
can be dangerous, care should be taken when exploring the spray cliff
community.
Spray cliff communities
occur on cliffs, ledges, and gently sloping rock faces that are frequently
wetted by the spray or splash from adjacent waterfalls. Because constant
spray and/or splash from the waterfall provide high humidity and moisture,
mosses and liverworts are often abundant. Vascular plants are found in
pockets of shallow soil that collect in tiny crevices and ledges of the
rock face. Temperature is moderated in these communities by spray water
and because it is sheltered from the sun and wind.
Although the spray
cliff community is not high in species diversity, it does harbor a distinct
assemblage of plants. The canopy from adjacent forest communities often
provides some shade, but there are no trees in the spray cliff community,
probably due to the combination of steepness, lack of soil, and wetness.
A few dwarfed stems
of Canada hemlock (Tsuga
canadensis),
northern wild raisin (Viburnum
cassinoides),
great laurel (Rhododendron
maximum),
or mountain laurel (Kalmia
latifolia) are sometimes present.
Herbs that are typically
found here include
Appalachian bluet
(Houstonia serpyllifolia),
mountain meadow rue (Thalictrum
clavatum),
branch-lettuce (Saxifraga
micranthidifolia),
meadow spikemoss (Selaginella
apoda),
jewelweed (Impatiens capensis),
common rockcap fern (Polypodium
virginianum),
galax (Galax urceolata)
and maidenhair spleenwort (Asplenium
trichomanes).
Rare species are only
known from a few spray cliff communities and include
American water-pennywort
(Hydrocotyle americana)
and cave alumroot (Heuchera
parviflora),
which is found in
either moist or dry overhanging rock ledges.
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