True or False - All plants have round stems.
Actually, the statement is false. While many plants have round stems, most sedges have triangular shaped stems and some plants such as mints have square stems. Sedge stems and leaves often contain silica (the material that is used in making glass) and are thus very sharp. The long silica lined edges can make walking in wetlands where sedges often grow a memorably unpleasant experience. Most sedges have solid stems, compared to grasses which have hollow stems, and leaves in three rows. The leaves are often slender and have a fused basal sheath that clasps the stem.
There are about 100 genera and 4000 to 5000 species of sedges world-wide, but only about 75 species inhabit Rocky Mountain National Park. All but nine of these species are members of the genus Carex, one of the most numerous genera world-wide. Carex and Kobresia (another sedge) are dominant plants of the tundra and are important food sources for elk. Kobresia dominates in dry, windswept areas of the tundra where snow does not accumulate in the winter. Carex tends to be found in areas that are more moist, or where winter snows provide protection from the bitter cold.
While sedges are flowering plants, the flowers are not showy. Because sedges are wind pollinated, they don't have to attract the attention of a pollinator. Because they are so wide-spread and dominant in some habitats, this minimalist approach to flower production seems to be very effective. There is fossil evidence of sedges from the Eocene (54.8 to 33.7 million years ago).
Last updated: March 31, 2012