Persistence (botany)


Persistence is the retention of plant organs, such as flowers, seeds, or leaves, after their normal function has been completed, in contrast with the shedding of deciduous organs after their purpose has been fulfilled. Absence or presence of persistent plant organs can be a helpful clue in plant identification, and may be one of many types of anatomical details noted in the species descriptions or dichotomous keys of plant identification guides. Many species of woody plants with persistent fruit provide an important food source for birds and other wildlife in winter.
The terms persistent and deciduous are not used in a consistent manner by botanists. Related terms such as long-persistent, generally deciduous, and caducous suggest that some plant parts are more persistent than others. However, these terms lack clear definitions.

Species with persistent parts

There are numerous herbaceous and woody plant species that produce persistent parts such as bud scales, sepals, fronds, fruits, seeds, strobili or styles. Note that the trait of persistence exhibited by a given species within a genus may not be exhibited by all species within the genus. For example, the Equisetum genus includes some species that have persistent strobili while other species have deciduous strobili.
SpeciesPersistent part
Berberis bealei bud scales
Berberis swaseyi bud scales
Berberis trifoliolata bud scales
Hamamelis virginiana calyx
Matteuccia struthiopteris frond
Onoclea sensibilis frond
Aronia arbutifolia fruit
Berberis thunbergii fruit
Cephalanthus occidentalis fruit
Chimaphila umbellata fruit
Clethra alnifolia fruit
Cornus florida fruit
Cotoneaster apiculatus fruit
Crataegus phaenopyrum fruit
Hamamelis virginiana fruit
Ilex verticillata fruit
Malus coronaria fruit
Malus sargentii fruit
Orthilia secunda fruit
Oxydendrum arboreum fruit
Rhus typhina fruit
Allium tricoccum seed
Eriophorum virginicum seed
Equisetum praealtum stem
Larix occidentalis strobilus
Picea mariana strobilus
Pinus banksiana strobilus
Clematis terniflora style
Orthilia secunda style

Common witch-hazel may have a persistent calyx or a persistent fruit. After flowering in the fall, the sepals and pollinated ovary persist during the winter months. After the ovary is fertilized in the spring, it fuses with the calyx to form a greenish fruit, which eventually becomes woody and brown. In the fall, the ripe fruit suddenly splits, explosively dispersing black seeds up to. The empty capsule persists after the seeds are dispersed.