Bud - Types of Buds

Types of Buds

Buds are often useful in the identification of plants, especially for woody plants in winter when leaves have fallen. Buds may be classified and described according to different criteria: location, status, morphology, and function.

Botanists commonly use the following terms:

• for location:
  • terminal, when located at the tip of a stem (apical is equivalent but rather reserved for the one at the top of the plant);
  • axillary, when located in the axil of a leaf (lateral is the equivalent but some adventitious buds may be lateral too);
  • adventitious, when occurring elsewhere, for example on trunk or on roots (some adventitious buds may be former axillary ones reduced and hidden under the bark, other adventitious buds are completely new formed ones).

• for status:
  • accessory, for secondary buds formed besides a principal bud (axillary or terminal);
  • resting, for buds that form at the end of a growth season, which will lie dormant until onset of the next growth season;
  • dormant or latent, for buds whose growth has been delayed for a rather long time. The term is usable as a synonym of resting, but is rather employed for buds waiting undeveloped for years, for example epicormic buds;
  • pseudoterminal, for an axillary bud taking over the function of a terminal bud (characteristic of species whose growth is sympodial: terminal bud dies and is replaced by the closer axillary bud, for examples beech, persimmon, Platanus have sympodial growth).

• for morphology:
  • scaly or covered, when scales (which are in fact transformed and reduced leaves) cover and protect the embryonic parts;
  • naked, when not covered by scales;
  • hairy, when also protected by hairs (it may apply either to scaly or to naked buds).

• for function:
  • vegetative, if only containing vegetative pieces: embryonic shoot with leaves (a leaf bud is the same);
  • reproductive, if containing embryonic flower(s) (a flower bud is the same);
  • mixed, if containing both embryonic leaves and flowers.