Plant morphology share the same basic structure and development as leaves in other plants, and therefore cactus spines are homologous to leaves as well. This aspect of plant morphology overlaps with the study of plant evolution and paleobotany. Secondly, plant morphology observes both the vegetative (somatic) structures of plants, as well as the reproductive structures. The vegetative structures of vascular plants includes the study of the shoot system, composed of stems and leaves, as well as the root system. The reproductive structures are more varied, and are usually specific to a particular group of plants, such as flowers and seeds, fern sori,
Ornamental bulbous plant such as "Crocus cartwrightianus", flower in the autumn, either at the same time as the leaves appear or before. Others, such as "Arum creticum", produce leaves in the autumn which last through the winter until the plant flowers in the spring. Summer drought occurs particularly, but not exclusively, in those regions of the world with a Mediterranean climate, which are rich in bulbous plants. Such regions include the Mediterranean itself through to Central Asia, the south west of South Africa, the south west of Australia, parts of the western United States, such as California, and parts of western South America,