Geoscience Reference
In-Depth Information
Figure 6-15.
Mangrove on the island of Carabane,
which is part of the delta of the Casamance River,
Senegal. The stilt roots support the mangrove in
shallow water or on emergent shore. Modii ed from
original photograph by Ji-Elle; obtained from
Wikimedia Commons
Figure 6-14.
Red admiral butterl y (
Vanessa atalanta
)
feeds on the dazzling white l ower cluster of the
buttonbush (
Cephalanthus occidentalis
). See Color
Plate 6-14. Photo by J.S. Aber and S.W. Aber, Lake
Kahola, Kansas, United States.
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http://commons.
wikimedia.org/
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.
Peat moss
(
Sphagnum
sp.) -
Sphagnum
moss includes many species that inhabit bogs
and accumulate peat (see Color Plate 5-12). For
example, about 40 species are found in bogs of
Finland (Laine and Vasander 1996). Through its
biochemistry,
Sphagnum
creates highly acidic
conditions that exclude most other plants, and
moss is not eaten by animals. These factors
allow
Sphagnum
to expand and accumulate
peaty soil in bogs, which are particularly
common in middle to high latitudes in North
America and Eurasia.
Brook cress
(
Cardamine cordifolia
) - Small
four-petaled l owers cluster on the ends of leafy
stems, up to 2 feet (60 cm) tall, in bushy clumps
beside spring-fed streams and in wet meadows
in montane and subalpine habitats (Dahms
1999). Also known as bitter cress, this plant is a
member of the mustard family (Cruciferae); its
l avor is stronger than watercress (see Fig. 4-8).
and subtropical coastal marine environments
worldwide (Fig. 6-15). Their habitats depend
primarily on water salinity and depth. Some are
primarily shoreline trees; others fall in the emer-
gent category. Three species of mangroves are
common in the Florida Everglades and Keys
region (Stevenson 1969):
• Red mangrove (
Rhizophora mangle
). Lives
in shallow marine water of bays and estuar-
ies (see Fig. 6-4). The tree is supported by
curving stilt (or prop) roots. Trees may form
dense thickets that protect the coastline
from storm erosion and provide cover for
wildlife. The seed pod (radicle) l oats to
become rooted elsewhere.
• Black mangrove (
Avicennia germinans
).
Grows on land in the saline tidal zone,
inland from the open sea (see Fig. 6-2).
Numerous breathing roots, called pneumato-
phores, grow up from soil for air exchange.
• White mangrove (
Laguncularia racemosa
).
Inhabits the higher, landward, less salty
zone. It lacks prop roots and has only a few
pneumatophores.
6.2.2 Emergent plants
Next are emergent plants that are rooted in soil
that is underwater most of the time. These
plants grow up through the water, so that stems,
leaves and l owers emerge in air above water
