Onocleaceae is a small family of terrestrial

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except t ...

s in the order

Polypodiales The 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 tropical, semitropical and temperate areas. Description Polypodiale ...

. It is placed in the suborder

Aspleniineae Aspleniineae is a suborder of ferns in the order Polypodiales. It is equivalent to the clade eupolypods II in earlier systems; it is also treated as a single very broadly defined family Aspleniaceae. The suborder generally corresponds with the o ...

in the

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

classification of 2016 (PPG I). Alternatively, the family, along with

Blechnaceae Blechnaceae is a family of ferns in the order Polypodiales, with a cosmopolitan distribution. Its status as a family and the number of genera included have both varied considerably. In the Pteridophyte Phylogeny Group classification of 2016 ( ...

, may be placed in a very broadly defined family

Aspleniaceae The Aspleniaceae (spleenworts) are a family of ferns, included in the order Polypodiales. The composition and classification of the family have been subject to considerable changes. In particular, there is a narrow circumscription, Aspleniaceae ...

as the subfamily Blechnoideae. The family may contain from one to four genera, consisting of five species largely in north temperate climes. The four genera, ''

Matteuccia ''Matteuccia'' is a genus of ferns with one species: ''Matteuccia struthiopteris'' ( common names ostrich fern, fiddlehead fern, or shuttlecock fern). The species epithet ''struthiopteris'' comes from Ancient Greek words () "ostrich" and () "fe ...

'', ''

Onoclea ''Onoclea'' is a genus of plants in the family Onocleaceae, native to moist habitats in eastern Asia and eastern North America. They are deciduous ferns with sterile fronds arising from creeping rhizomes In botany and dendrology, a rhizome ...

'', ''

Onocleopsis ''Onocleopsis'' is a genus of ferns in the family Onocleaceae Onocleaceae is a small family of terrestrial ferns in the order Polypodiales. It is placed in the suborder Aspleniineae in the Pteridophyte Phylogeny Group classification of 2016 (P ...

'' and '' Pentarhizidium'', may be included under the single genus ''Onoclea''.

Description

Members of the family have the following characteristics, being distinguished by having strongly dimorphic

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, with the fertile fronds different from the sterile fronds. The

rhizomes In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow hori ...

are long- to short-creeping to ascending, and sometimes stoloniferous (''Matteuccia'' and ''Onocleopsis''). The leaves are strongly dimorphic and the petioles have two vascular bundles uniting distally into a gutter-shape. The blades are

pinnatifid Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and i ...

or pinnate-pinnatifid. The veins are free or anastomosing, lacking included veinlets. The

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s are reniform, brownish to green. The sori are enclosed (sometimes tightly) by reflexed laminar margins, also with membranous, often fugacious true indusia.

Taxonomy

Formerly, the two species in the genus ''Pentarhizidium'' were considered to be members of ''Matteuccia'', but genetic analysis has determined that they compose a basal sister clade to the rest of the family. This family has been determined by genetic analysis to be closely allied to the

, within the clade of families sometimes known as Blechnales (which includes the athyrioid ferns and asplenioid ferns as well) (this clade is often treated as part of the order

however). ''

Matteuccia struthiopteris ''Matteuccia'' is a genus of ferns with one species: ''Matteuccia struthiopteris'' (common names ostrich fern, fiddlehead fern, or shuttlecock fern). The species epithet ''struthiopteris'' comes from Ancient Greek words () "ostrich" and () "fer ...

'' was previously classified under the

Dryopteridaceae The Dryopteridaceae are a Family (biology), family of leptosporangiate ferns in the Order (biology), order Polypodiales. They are known Common name, colloquially as the wood ferns. In the Pteridophyte Phylogeny Group classification of 2016 (PPG&n ...

, and still is by the

USDA The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of com ...

Phylogenetic relationships

The following cladogram for the suborder

(as eupolypods II), based on Lehtonen (2011), and Rothfels & al. (2012), shows a likely

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

relationship between the Onocleaceae and the other families of the clade.

Species

Four genera, with a total of five species, are accepted. * ''Matteuccia'' ** ''

'' (ostrich fern) - wide distribution including North America, Europe, and Asia * ''Onoclea'' ** ''

Onoclea sensibilis ''Onoclea sensibilis'', the sensitive fern, also known as the bead fern, is a coarse-textured, medium to large-sized deciduous perennial fern. The name comes from its sensitivity to frost, the fronds dying quickly when first touched by it. It is ...

'' (sensitive fern) - North America and eastern Asia, with the American and Asian populations being recognized as distinct varieties * ''Onocleopsis'' ** '' Onocleopsis hintonii'' - found in a restricted range of wet mountain canyons in southern Mexico and Guatemala; some botanists (especially Masahiro Kato) consider this to be a species of ''Matteuccia'' * '' Pentarhizidium'' ** '' Pentarhizidium orientale'' - eastern Asia as far south as the

Himalayas The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over 100 ...

** '' Pentarhizidium intermedium'' - China to India A molecular phylogenetic analysis in 2011 suggested that the four Onocleacae genera are so closely related that they could be included under the single genus ''Onoclea''. A possible phylogenic relationship between Onocleaceae species (line lengths are not significant) is shown below. The

classification of 2016 (PPG I) maintained the four genera.

References

{{Taxonbar, from=Q139173 Polypodiales Fern families