A catkin or ament is a slim, cylindrical
flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...
cluster (a
spike
Spike, spikes, or spiking may refer to:
Arts, entertainment, and media
Books
* ''The Spike'' (novel), a novel by Arnaud de Borchgrave
* ''The Spike'' (book), a nonfiction book by Damien Broderick
* ''The Spike'', a starship in Peter F. Hamilto ...
), with inconspicuous or no
petals, usually
wind
Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few ho ...
-
pollinated
Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, a ...
(
anemophilous
Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges, and rushes. Other common anemophilous plan ...
) but sometimes insect-pollinated (as in ''
Salix
Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...
''). They contain many, usually
unisexual
Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproducti ...
flowers, arranged closely along a central stem that is often drooping. They are found in many
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...
families, including
Betulaceae
Betulaceae, the birch family, includes six genera of deciduous nut-bearing trees and shrubs, including the birches, alders, hazels, hornbeams, hazel-hornbeam, and hop-hornbeams numbering a total of 167 species. They are mostly natives of the ...
,
Fagaceae,
Moraceae
The Moraceae — often called the mulberry family or fig family — are a family of flowering plants comprising about 38 genera and over 1100 species. Most are widespread in tropical and subtropical regions, less so in temperate climates; however ...
, and
Salicaceae
The Salicaceae is the willow family of flowering plants. The traditional family (Salicaceae ''sensu stricto'') included the willows, poplar, aspen, and cottonwoods. Genetic studies summarized by the Angiosperm Phylogeny Group (APG) have greatly ...
.
Occurrence
Catkin-bearing plants include many
trees
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are u ...
or
shrubs such as
birch
A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' contains ...
,
willow
Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist so ...
,
aspen
Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section ''Populus'', of the '' Populus'' genus.
Species
These species are called aspens:
*'' Populus adenopoda'' – Chinese aspen (Chin ...
,
hickory,
sweet chestnut
''Castanea sativa'', the sweet chestnut, Spanish chestnut or just chestnut, is a species of tree in the family Fagaceae, native to Southern Europe and Asia Minor, and widely cultivated throughout the temperate world. A substantial, long-lived ...
, and
sweetfern (''Comptonia'').
In many of these plants, only the male flowers form catkins, and the female flowers are single (
hazel,
oak
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
), a cone (
alder
Alders are trees comprising the genus ''Alnus'' in the birch family Betulaceae. The genus comprises about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few sp ...
), or other types (
mulberry). In other plants (such as
poplar), both male and female flowers are borne in catkins.
In Britain, they can be seen in January or February, when many trees are bare for winter. They can even occur in December.
Evolution
For some time, catkins were believed to be a key
synapomorphy
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...
among the proposed
Hamamelididae
Hamamelididae is an obsolete botanical name at the rank of subclass.
Because some hamamelidid members bear aments (''i.e.'', catkins), this subclass has been formerly known as ''Amentiferae''. Based on molecular phylogeny works, Hamamelididae app ...
, also known as Amentiferae (i.e., literally plants ''bearing aments''). Based on
molecular phylogeny
Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...
work, it is now believed that Hamamelididae is a
polyphyletic
A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...
group.
[ Savolainen, V., M. W. Chase, S. B. Hoot, C. M. Morton, D. E. Soltis, C. Bayer, M. F. Fay, A. Y. De Bruijn, S. Sullivan, and Y.-L. Qiu. 2000. Phylogenetics of flowering plants based on combined analysis of plastid ''atpB'' and ''rbcL'' gene sequences. Systematic Biology 49:306-362.][Soltis, D. E. et alii. (28 authors). 2011. "Angiosperm phylogeny: 17 genes, 640 taxa". ''American Journal of Botany'' 98(4):704-730. ] This suggests that the catkin flower arrangement has arisen at least twice independently by
convergent evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...
, in
Fagales
The Fagales are an order of flowering plants, including some of the best-known trees. The order name is derived from genus ''Fagus'', beeches. They belong among the rosid group of dicotyledons. The families and genera currently included are as ...
and in
Salicaceae
The Salicaceae is the willow family of flowering plants. The traditional family (Salicaceae ''sensu stricto'') included the willows, poplar, aspen, and cottonwoods. Genetic studies summarized by the Angiosperm Phylogeny Group (APG) have greatly ...
.
[Cronk Q. C. B., Needham I., and Rudall P. J. 2015. Evolution of catkins: inflorescence morphology of selected Salicaceae in an evolutionary and developmental context. ''Frontiers in Plant Science''. 2015; 6: 1030. ] Such a convergent evolution raises questions about what the
ancestral
An ancestor, also known as a forefather, fore-elder or a forebear, is a parent or ( recursively) the parent of an antecedent (i.e., a grandparent, great-grandparent, great-great-grandparent and so forth). ''Ancestor'' is "any person from wh ...
inflorescence characters might be and how catkins did evolve in these two lineages.
Etymology
The word ''catkin'' is a
loanword
A loanword (also loan word or loan-word) is a word at least partly assimilated from one language (the donor language) into another language. This is in contrast to cognates, which are words in two or more languages that are similar because t ...
from the
Middle Dutch
Middle Dutch is a collective name for a number of closely related West Germanic dialects whose ancestor was Old Dutch. It was spoken and written between 1150 and 1500. Until the advent of Modern Dutch after 1500 or c. 1550, there was no overarc ...
''katteken'', meaning "
kitten" (compare also
German
German(s) may refer to:
* Germany (of or related to)
** Germania (historical use)
* Germans, citizens of Germany, people of German ancestry, or native speakers of the German language
** For citizens of Germany, see also German nationality law
**Ge ...
''Kätzchen''). This name is due either to the resemblance of the lengthy sorts of catkins to a kitten's tail, or to the fine fur found on some catkins. ''Ament'' is from the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''amentum'', meaning "thong" or "strap".
Gallery
Fagales
The Fagales are an order of flowering plants, including some of the best-known trees. The order name is derived from genus ''Fagus'', beeches. They belong among the rosid group of dicotyledons. The families and genera currently included are as ...
'')
File:Catkins Corylus avellana-Mont Bart-5124~2015 12 26.JPG , Young male catkins of