Life Cycle and Structure
Perennial plants can be short-lived (only a few years) or they can be long-lived, as are some woody plants like trees. They include a wide assortment of plant groups from ferns and liverworts to the highly diverse flowering plants like orchids and grasses.
Plants that flower and fruit only once and then die are termed monocarpic or semelparous. However, most perennials are polycarpic (or iteroparous), flowering over many seasons in their lifetime.
Perennials typically grow structures that allow them to adapt to living from one year to the next through a form of vegetative reproduction rather than seeding. These structures include bulbs, tubers, woody crowns, rhizomes plus others. They might have specialized stems or crowns that allow them to survive periods of dormancy over cold or dry seasons during the year. Annuals produce seeds to continue the species as a new generation while the growing season is suitable, and the seeds survive over the cold or dry period to begin growth when the conditions are again suitable.
Many perennials have specialized to survive under extreme environmental conditions: some have adapted to survive hot and dry conditions, or to survive under cold temperatures. Those plants tend to invest a lot of resource into their adaptations and often do not flower and set seed until after a few years of growth. Many perennials produce relatively large seeds, which can have an advantage, with larger seedlings produced after germination that can better compete with other plants. Some annuals produce many more seeds per plant in one season, while some (polycarpic) perennials are not under the same pressure to produce large numbers of seeds but can produce seeds over many years.
Read more about this topic: Perennial Plant
Famous quotes containing the words life, cycle and/or structure:
“I have given the best of myself and the best work of my life to help obtain political freedom for women, knowing that upon this rests the hope not only of the freedom of men but of the onward civilization of the world.”
—Mary S. Anthony (18271907)
“The cycle of the machine is now coming to an end. Man has learned much in the hard discipline and the shrewd, unflinching grasp of practical possibilities that the machine has provided in the last three centuries: but we can no more continue to live in the world of the machine than we could live successfully on the barren surface of the moon.”
—Lewis Mumford (18951990)
“... the structure of our public morality crashed to earth. Above its grave a tombstone read, Be toleranteven of evil. Logically the next step would be to say to our commonwealths criminals, I disagree that its all right to rob and murder, but naturally I respect your opinion. Tolerance is only complacence when it makes no distinction between right and wrong.”
—Sarah Patton Boyle, U.S. civil rights activist and author. The Desegregated Heart, part 2, ch. 2 (1962)