Basics of Life cycle adaptations

Personal notes for RHS Level 2 Certificate in the Principles of Plant Growth and Development
Unit 1: Plant Science 1: Lifecycle adaptations: AO1

Life cycle adaptations are the ways that plants have evolved to survive and reproduce in different environments. Based on their life cycle, plants can be classified into five categories:

• Ephemeral plants are those that have several life cycles in one growing season. They can germinate, grow, flower, and produce seeds in a short period of time, usually in response to favourable conditions such as rainfall. They can increase in numbers rapidly and colonize disturbed habitats. An example of an ephemeral plant is groundsel (Senecio vulgaris).
• Annual plants are those that complete their life cycle in one year or growing season. They germinate from seeds, grow, flower, produce seeds, and die within a year. They can be hardy, half-hardy, or tender, depending on their ability to withstand frost and low temperatures. Examples of annual plants are zinnia (Zinnia elegans) and marigold (Tagetes patula).
• Biennial plants are those that complete their life cycle in two years or growing seasons. They germinate from seeds and grow vegetatively in the first year, then flower, produce seeds, and die in the second year. Some plants that are botanically perennials are grown as biennials because they perform poorly after flowering. Examples of biennial plants are foxglove (Digitalis purpurea) and wallflower (Erysimum cheiri).
• Perennial plants are those that live for more than two years or growing seasons. They can be herbaceous or woody, depending on the presence or absence of secondary growth in their stems. Herbaceous perennials are non-woody plants that die back to a rootstock each autumn and regrow in the following spring.
  Examples of herbaceous perennials are hop (Humulus lupulus) and peony (Paeonia lactiflora).
  Woody perennials are plants that maintain live woody stems throughout the year and exhibit secondary growth. Examples of woody perennials are lilac (Syringa vulgaris) and oak (Quercus spp.).