BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Cladium jamaicense | Sawgrass 



GENERAL BOTANICAL CHARACTERISTICS : 
Sawgrass is a coarse, rhizomatous, perennial sedge.  The flat
0.5-inch-wide (1.2 cm) leaves have saw-toothed margins, and are seldom
less than 3 feet (1 m) long, and typically 6 to 10 feet (2-3 m) long
[8].  Sawgrass often grows in dense, nearly monospecific stands which
result from an extensive network of rhizomes.  Apical meristems arise
from the top of the rhizomes.  In the Everglades, Yates [28] found that
rhizomes were generally within the top 4 inches (10 cm) in marl soil,
and within the top 6 to 8 inches (15-20 cm) of peat soil.  On
permanently flooded sites sawgrass forms tussocks and the roots and
rhizomes grow above the sediment surface [28].


RAUNKIAER LIFE FORM : 
   Cryptophyte


REGENERATION PROCESSES : 
Sawgrass's predominant mode of reproduction is vegetative through an
extensive rhizome system [1].

Sexual reproduction via seedling establishment is generally
insignificant [1,24].  Although seeds are produced each year in most
stands, seedling establishment and survival are rare.  Seed production
varies greatly from year to year, and from one location to another.
Occasionally large numbers of seeds are produced, but viability is
usually low.  Germination of southern Florida seed averaged about 20
percent [1].  In southern Florida, seedfall begins in early August,
which coincides with the wet season.  The floating seeds are primarily
water-dispersed.  Some seeds are also dispersed by waterfowl after
passing through the digestive tract unharmed [28].  Naturally
germinating seedlings have been observed in the fall following summer
seed dispersal.  They are usually found in open areas with wet but
unflooded soils.  Seedling survival is poor because the seedlings are
intolerant of fluctuating water levels and are killed by either dry-down
or flooding [1].


SITE CHARACTERISTICS : 
Sawgrass primarily grows in shallow, freshwater marshes, although it
occasionally grows in and may even dominate some brackish water areas
[27,29].  It grows best on seasonally flooded sites in which the period
of inundation is 6 to 9 months, or longer [14,15,27].  Optimum water
depth is about 1 foot (0.28 m) [1].  Sawgrass grows best on deep organic
soils.  In fact, the vast sawgrass marshes of the Everglades grow on
peat and muck deposits up to 13 feet (4 m) deep [24].  Sawgrass also
grows on marl soil and even in small solution holes in rocky areas, but
with decreased vigor [8].  Sawgrass has extremely low nutrient
requirements.  It dominates the Everglade's organic peats which are
deficient in minor elements and have low quantities of available
phosphorus and potash [14,24].


SUCCESSIONAL STATUS : 
Sawgrass stands are relatively stable on sites shallowly flooded for
most of the year.  However, when flooding depth or hydroperiod is
altered, sawgrass is replaced by other communities.  When water levels
increase, sawgrass is often replaced by cattails, pickerelweed
(Pontederia lanceolata), fire flag (Thalia geniculata), maidencane,
spikerush, white water lily (Nymphaea odorata), neverwet (Orontium
aquaticum), and yellow lotus (Nelumbo lutea) [1,14].  When water levels
are reduced or hydroperiods shortened, drier site species replace
sawgrass.  These include wax myrtle (Myrica cerifera), saltbush
(Baccharis spp.), buttonwood (Concarpus erecta), red mangrove
(Rhizophora mangle), plume grass (Erianthus giganteus), muhly grass
(Muhlenbergia spp.), marsh fleabane (Pluchea spp.), fennels (Eupatorium
spp.), hemp vine (Mikania spp.), pigweed (Acnida cuspidata), bluestems
(Andropogon spp.), and giant bristlegrass (Setaria magna) [5,15,27].

In areas of the Everglades receiving nutrient rich inflows such as along
canal system inflow gates, sawgrass stands are being invaded by
Dominican cattail (T. domingensis) [6].  

Primarily a freshwater species, sawgrass has been replaced by saltmarsh
species in the southern Everglades as brackish water moves farther
inland due to reduced freshwater inflows and the slowly rising sea level
[27].


SEASONAL DEVELOPMENT : 
In Florida, sawgrass vegetative growth is not winter dormant.  In fact,
it is one of the most cold-tolerant of Florida's marsh species [24].
Leaf growth continues year-round but does slow somewhat during the dry
season [11].  Flowering stalks are first visible in March or April.
They grow rapidly and are in full flower by June or July.  Seeds mature
by August, and thereafter begin dropping [1,28].  After flowering, the
culm and its associated leaves and rhizome die.  Death and decay are
rapid [1].

Related categories for Species: Cladium jamaicense | Sawgrass