How does a sedge differ from a grass?

How does a sedge differ from a grass?

• A. Grasses have triangular stems
• B. Sedges have round stems and two rows of leaves
• C. Sedges are evergreen and have only one leaf
• D. Sedges have triangular stems and three rows of leaves

Answer: (D)

The key idea is how to tell sedges from grasses by structure. Sedges have triangular, solid stems and leaves arranged in three ranks around the stem, while grasses have round, hollow stems and leaves in two ranks. The statement that sedges have triangular stems and three rows of leaves best describes these distinguishing features, so it’s the right answer. The other statements misstate these traits: grasses aren’t triangular-stemmed; sedges aren’t defined by round stems with two leaf rows; and the evergreen/one-leaf idea isn’t a reliable distinction for sedges.

The key idea is how to tell sedges from grasses by structure. Sedges have triangular, solid stems and leaves arranged in three ranks around the stem, while grasses have round, hollow stems and leaves in two ranks. The statement that sedges have triangular stems and three rows of leaves best describes these distinguishing features, so it’s the right answer. The other statements misstate these traits: grasses aren’t triangular-stemmed; sedges aren’t defined by round stems with two leaf rows; and the evergreen/one-leaf idea isn’t a reliable distinction for sedges.