Sedges

    Sedges and grasses occur in similar environments and appear similar in general aspect. They differ in several important aspects, however

• Grasses have stems with round cross sections, but sedges have triangular cross sections. This is more evident when you roll the stem between thumb and index finger. The grass will roll easily, but the sedge will resist along its triangular faces. "Sedges have Edges" is the botanical mantra to remember this aspect of symmetry.
  
• Grasses leaves emerge from in pairs alternately, while sedge leaves branch from the central stem in three's. This is most evident from above, giving the sedge a fuller footprint, clearly triangular in general outline.
  
• Grasses have mostly hollow stems; sedges have solid stems.
  
• Grass fruit (grain) is a caryopsis in which the seed is fused to its covering. Think of a grain of corn in which the seed (the little white lens) is fused to the yellow part; we eat both. Sedge fruit is an achene in which the seed is separate. Think of a sunflower seed in which the seed we eat is loosely attached to its covering which we spit out.