Cyperus alopecuroides Rottb. (Juncellus alopecuroides (Rottb.)
C.B. Clarke)
C. alopecuroides is a huge sedge
discovered in a reclaimed wetland near Fort Meade (Polk County), Florida. This is only the
second
finding of this impressive species in the Western Hemisphere. C. alopecuroides
grows up to twelve
feet tall, with bracts up to six feet long! It has broad bracts and leaf blades and a branched
inflorescence with spikes of densely clustered golden-brown spikelets. Its leaf margins are
serrated
and sharp. This species is widely distributed in the tropics of the Old World where it may form
extensive stands and floating mats. According to Bryson, of the four species discussed here, this
one
likely would become the most troublesome weed in Florida conditions.
Cyperus iria L., rice flatsedge
Rice flatsedge, is in Holm's list of the world's worst weeds. An Asiatic
species, it
was probably introduced in the 1700 or 1800s. Rice flatsedge has become common throughout
the
southeastern United States. Once established in wet situations, rice flatsedge can persist without
wet
feet, and become a major weed in rice, cotton, soybean and other crops.
Cyperus difformis L., smallflower umbrella sedge
Smallflower umbrella sedge, is listed in Holm's list of the world's worst
weeds,
being a problem especially in rice, sugarcane, tea and corn. Smallflower umbrella sedge is native
to
the tropics of the Old World, but is spreading well outside its native range. This sedge has a
relatively
short generation period of as little as 4 to 6 weeks from seed to seed as opposed to a more usual
one
or two generations a year: Bryson notes that such a short life cycle is more like that of an insect
than
a plant. Smallflower umbrella sedge seems to be spreading along major waterways and in rice
production areas of the U.S. In California, this plant has become resistant to rice-field herbicides.
In
Asian rice production, where herbicides are not used, this weed may account for 60-70% of the
total
biomass of the rice field.
Cyperus prolifer Lam., dwarf papyrus or miniature papyrus
Dwarf papyrus is commonly sold as an ornamental for
use in water gardens, similar to papyrus (Cyperus papyrus L.), and false papyrus
(Cyperus
involucratus Poir.). This species spreads vegetatively, simply by leaning over. New
daughter plants
grow in the inflorescence; as the new shoots become heavier, the mother plant leans over,
eventually
reaching the mud whereupon the daughter plants attach, grow and spread. In central Florida, this
sedge apparently has escaped from cultivation and is found growing in floating mats and along
margins of limesink lakes.