persistence (botany)
{{short description|Retention of plant organs that normally are shed}}
File:Equisetum arvense-271.JPG of Equisetum arvense]]
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.{{cite book |last1=Hitchcock |first1=C. Leo |last2=Cronquist |first2=Arthur |date=2018 |title=Flora of the Pacific Northwest |edition=2nd|page=xxxviii, xliii |publisher= University of Washington Press |location= Seattle |isbn=978-0-29574-288-5}} 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.{{Cite web|url=https://employees.csbsju.edu/ssaupe/biol308/Lecture/keys.htm |title=Plant Identification (featuring Taxonomic Keys) |last1=Saupe |first1=Stephen |website=College of St. Benedict/St. John's University|access-date=2022-05-01}} Many species of woody plants with persistent fruit provide an important food source for birds and other wildlife in winter.{{r|Jauron 2000}}
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.{{r|Harms 1}}
Species with persistent parts
There are numerous herbaceous and woody plant species that produce persistent parts such as bud scales, sepals ({{Wikt-lang|en|calyx|italic=no}}), fronds, fruits, seeds, strobili (cones) 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.{{sfnp|Pojar|MacKinnon|1994|pages=428–431}}
Common witch-hazel (Hamamelis virginiana) may have a persistent calyx or a persistent fruit (or both at the same time). After flowering in the fall,{{r|FNA:220006023}} the sepals (calyx) and pollinated ovary persist during the winter months.{{r|MGNV}} After the ovary is fertilized in the spring, it fuses with the calyx to form a greenish fruit, which eventually becomes woody and brown.{{r|FNA:114541}} In the fall, the ripe fruit suddenly splits, explosively dispersing black seeds up to {{convert|10|m|ft|0|abbr=on}}. The empty capsule persists after the seeds are dispersed.{{r|Guertin et al. 2017}}
Image gallery
File:20201210Larix decidua2.jpg|Larix decidua has persistent seed cones.
File:Equisetum arvense kz01.jpg|Equisetum arvense has persistent strobili.
File:Cornus florida Cherokee Princess 10zz.jpg|This Cornus florida cultivar has persistent fruit into winter.
File:Pinus banksiana 2021 06 20 Kumpula 0352.jpg|Seed cones of Pinus banksiana persist on branches long after seeds are released.
File:Berberis thunbergii berries.jpg|Berberis thunbergii has persistent fruit.
File:Ruhland, Brauhausplatz, Zierapfel (Malus sargentii) in Gebüschpflanzung, Früchte am Zweig, Herbst, 01.jpg|Malus sargentii has persistent fruit.
File:Nova Scotia DSC 2601 (2300122122).jpg|Serotinous seed cones of Picea mariana persist even after fire has caused the seeds to be released.
File:Red Chokeberry - Flickr - treegrow (1).jpg|Fruit of this Aronia arbutifolia cultivar persist through the winter and into early spring when new buds are emerging.
File:Hamamelis virginiana Vermont USA 2022-04-17-A.jpg|Hamamelis virginiana with persistent calyx in April
File:Hamamelis virginiana Vermont USA 2022-04-17-B.jpg|Hamamelis virginiana with persistent fruit in April
See also
References
Bibliography
- {{cite book |last1=Pojar |first1=Jim |last2=MacKinnon |first2=Andy |date=1994 |title=Plants of the Pacific Northwest Coast |edition=2nd |publisher=Lone Pine |isbn=978-1-55105-530-5}}