One differentiating characteristic between vascular and nonvascular plants is the lack of active transport structures in the nonvascular plants. How does the lack of xylem or phloem contribute to the smaller size of the nonvascular plants? Nonvascular plants are smaller because xylem and phloem help a plant stand up taller.
Nonvascular plants have other transport structures that are microscopic and therefore take up less room.
Nonvascular plants rely upon concentration gradients to move food and water, which only works over small distances.
Nonvascular plants are smaller because they don’t photosynthesize as much as vascular plants and don’t get enough food.