Which plant type often features triangular, pithy stems and leaves growing on three sides?

The correct answer is sedge, which is characterized by its triangular stems and leaves that typically grow in three ranks. This distinctive feature of sedges is a key identifying trait when distinguishing them from other types of plants.

In contrast, grasses usually have round stems and grow in a more upright form with leaves that grow alternately along the stem. Rushes also have a similar appearance to grasses, but they feature more solid stems rather than the triangular profile of sedges. Forbs are herbaceous flowering plants that do not necessarily conform to the specific stem shape found in sedges; they can have a range of leaf shapes and stem structures.

Understanding the specific morphological traits of these plant types is essential for accurate identification in agronomy and related fields.