Basic Biology Flashcards
Submersed Plants
Grow completely below the water surface and depend on the nutrients in the water for physiological functions. Reproduce primarily by fragmentation, vegetative reproductive structures, or seeds.
Emersed or Emergent Plants
Rooted in the sediments. They extend above the water surface and are self-supporting. Reproduce by vegetative means, form rhizomes or stolons in the hydrosoil; may colonize new areas by seed dispersal.
Free-Floating
Not attached to the substrate and float on the water surface or just below it. They have roots that extend into the water for nutrient uptake. Reproduce vegetatively, by fragmentation, and irregularly by seed.
Rooted Floating
Attached to the sediment and have leaves that float on the water surface. Some are supported by water alone, while others have a more rigid structure. Reproduce often by vegetative means.
Monocots
Once they germinate, they have a single primary leaf (or cotyledon); the cotyledon does not emerge above the soil surface and the first leaves you see are actually secondary or true leaves. Have narrow leaves with parallel veins and usually a fibrous root system. Most commonly reproduce by seed, stolons, or rhizomes. Growing point is ar or below the soil surface, particularly in young plants. Include the grasses.
Dicots
Have two primary leaves or cotyledons when they emerge from the soil. Cotyledons often do not look like the later true leaves. Usually have broad leaves with veins that form a net-like pattern. All species can reproduce by seed, but some have vegetative buds in the crown and still others reproduce by spreading rootstocks.
Annuals
Mature in one season and are propagated exclusively by seed. These plants die back to the substrate in the winter.
Summer… weeds grow from seeds that sprout in the spring, mature, and reproduce before dying in the winter.
Winter… weeds germinate in the fall or winter and grow until spring when they flower, produce seeds, and die.
Easily controlled by weeding, dredging, or herbicides.
Biennials
Require two years to develop and complete life cycles. In the first year, they often form a rosette (basal leaves), and a taproot, in the second year, the plant flowers, produces seeds and generally dies.
Perennials
Most aquatic weeds. Plants that live indefinitely; they may lose their foliage during the winter and die back to the substrate, but they recover in the spring. They flower and set seed without dying. Most are herbaceous (soft-bodied). Reproduce both vegetatively and by seed, can store food in their roots and rhizomes.
