''Sphaeropteris'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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 in the 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 ...

. It has been treated as a subgenus within the genus ''

Cyathea ''Cyathea'' is a genus of tree ferns, the type genus of the fern order Cyatheales. The genus name ''Cyathea'' is derived from the Greek ''kyatheion'', meaning "little cup", and refers to the cup-shaped sori on the underside of the fronds. ...

'', but is accepted 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).

Description

Species of ''Sphaeropteris'' have a treelike habit, usually with a single tall stem, and large fronds to or more in length. The stalk (stipe) of the frond is strawlike or purple in colour, with pale to brown scales. The sori (spore-bearing structures) are rounded, with or without indusia (covers). ''Sphaeropteris'' is now separated from the other genera in the family Cyatheaceae primarily on the basis of

molecular phylogenetic 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 ...

studies. However, the scales on the stalks (petioles) provide a morphological distinction. ''Sphaeropteris'' has scales without distinct margins, whereas the other genera have scales with distinct margins.

Taxonomy

The genus ''Sphaeropteris'' was erected by

Johann Jakob Bernhardi Johann Jakob Bernhardi (1 September 1774, in Erfurt – 13 May 1850, in Erfurt) was a German doctor and botanist. Biography Johann J. Bernhardi studied Medicine and Botany at the University of Erfurt, and after graduation practiced medicine for a ...

in 1801. It is placed in the family

. The division of the family into genera has had a long and controversial history. Three or four

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

s have been suggested based on

studies. The

classification of 2016 (PPG I) accepts three genera, related as shown in the cladogram below. ''Sphaeropteris'' is sister to the remaining members of the family. Older sources, such as the New Zealand Organisms Register , place ''Sphaeropteris'' within a very broadly defined ''Cyathea''.

Phylogeny

, the ''Checklist of Ferns and Lycophytes of the World'' accepted the following species:

Distribution and habitat

The native distribution of the genus ''Sphaeropteris'' extends from southern China down through eastern tropical Asia to New Zealand, with a separate area in Central America and north-western South America. Some species are also naturalized in Africa and western Australia. Species of ''Sphaeropteris'' are large plants and require space to grow. They usually prefer less shaded conditions than species of ''Alsophila''. They are found in rain forests and tropical montane forests, often in clearings or on the margins, from the canopy layer down to the

understorey In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but above ...

layer. They are also found in ravines, swamps and disturbed areas.

References

{{Taxonbar, from1=Q17166793 Fern genera