Dicksoniaceae is a group of

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

and warm temperate

fern The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

s, treated as a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

in the

Pteridophyte Phylogeny Group The Pteridophyte Phylogeny Group (PPG) is an informal international group of systematic botanists who collaborate to establish on the classification of pteridophytes ( lycophytes and ferns) that reflects knowledge about plant relationships discove ...

classification of 2016 (PPG I), and counting 30-40 species.Scaly Tree Ferns Have Slow and Steady Diversification
/ref> Alternatively, the family may be sunk into a very broadly defined family

Cyatheaceae The Cyatheaceae are a family of ferns, the scaly tree ferns, one of eight families in the order Cyatheales in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the family may defined much more broadly (Cyatheaceae ...

sensu lato ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular co ...

'' as the subfamily Dicksonioideae. Most of the

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

in the family are terrestrial ferns or have very short trunks compared to

tree fern Tree ferns are arborescent (tree-like) ferns that grow with a trunk (botany), trunk elevating the fronds above ground level, making them trees. Many extant tree ferns are members of the order Cyatheales, to which belong the families Cyatheaceae ( ...

s of the family Cyatheaceae ''

sensu stricto ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular c ...

''. However, some of the larger species can reach several metres in height. A number of others are

epiphyte An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

s. They are found mostly in

regions in the Southern Hemisphere, as far south as southern

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

. Larger tree ferns in the genus '' Cibotium'' were formerly included in Dicksoniaceae, but are now segregated as the family

Cibotiaceae ''Cibotium'' (from Greek , ''kibṓtion'', "little chest" or "box"), also known as manfern, is a genus of 11 species of tropical tree ferns. It is the only genus in family Cibotiaceae in the Pteridophyte Phylogeny Group classification of 2016 (P ...

Description

Species in the family are generally characterized by large pinnate

frond A frond is a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group. Other botanists allow the term frond to also apply to the lar ...

s, 1–4 m long. The family includes several species of tree ferns, which grow a single trunk, notably the species in '' Dicksonia''. All members of the family have long, tapering hairs composed of cells arranged end to end, unlike the scales characteristic of the Cyatheaceae ''s.l.''

Evolution

The family is thought to have arisen in the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

, based on molecular evidence. ''

Lophosoria Lophosoria is a genus of tree ferns within the family Dicksoniaceae. Although it is confined to tropical America in modern times, there is fossil evidence that it was once spread throughout Gondwana with the exception of New Zealand. Species ...

'' is known from fossil spores and leaf fragments from South America dating to the

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

. The oldest fossil of '' Dicksonia'' is known from the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

of Antarctica. The widespread Jurassic-Cretaceous herbaceous fern genus '' Coniopteris'' has historically been assigned to this family, but

cladistic analysis Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...

suggests that it is more closely related to the

Polypodiales The Order (biology), order Polypodiales encompasses the major lineages of polypod ferns, which comprise more than 80% of today's fern species. They are found in many parts of the world including Tropics, tropical, semitropical and Temperate clima ...

. Relationships of the three living genera, after.

Genera

Only three extant

are recognised in this

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

family:

References

Classification of Ferns and Allies
* Large, M.F. and J.E. Braggins (2004). ''Tree Ferns''. Timber Press. * Smith, A.R., K.M. Pryer, E. Schuettpelz, P. Korall, H. Schneider & P.G. Wolf 2006. ''Taxon'' 55(3): 705–731.

External links

* * {{Authority control Cyatheales Fern families