Freshwater aquaculture (2+1)

Practical 5 - Study of aquatic weeds

5.4. Marginal weeds

Typha sp.

• Found in slow moving streams and margins of lakes and river banks
• Perennial, robust, 2-4 m tall plant
• Stem without nodes, spongy, arising from subterraneous rhizomes
• Leave long, flat, linear, soft
• Spikes 15-30 cm long, drumstick like

Cyperus

• Triangular stems
• Leaves arise in rosette from stem base.
• Prominent inflorescence that has simple of compound flowers

Scirpus

• Perennial marginal weed found in shoreline marshes
• Usually soft leaves, small, clasped to stem base

Marsilia quadrifolia

• Small fern of shallow waters
• 50-100cm long stolon
• 4 flower-like leaflets placed on tip of a slender stalk.
• Common in ponds and paddy fields

Collocasia sp.

• Common marginal weed found in groups or rows along the margin of ponds.
• Leaves ovate, 6-20 inches in length and 3-12 inches wide
• Apex rounded, leaf margins dark green
• Petiole 3-4 feet long and green, violet or purple in colour
• Has tuberous rhizome
• Shoots and leaves eaten in certain areas