''Ceratopteris richardii'' is a

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 exce ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

belonging to the genus ''

Ceratopteris ''Ceratopteris'' is the only genus among homosporous ferns that is exclusively aquatic. It is pan-tropical and classified in the Parkerioideae subfamily of the family Pteridaceae. Description Erect aquatic or subaquatic ferns of moderate siz ...

'', one of only two

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

of the subfamily

Parkerioideae Parkerioideae, synonym Ceratopteridoideae, is one of the five subfamilies in the fern family Pteridaceae Pteridaceae is a family of ferns in the order Polypodiales, including some 1150 known species in ca 45 genera (depending on taxonomic opi ...

of the family

Pteridaceae Pteridaceae is a family of ferns in the order Polypodiales, including some 1150 known species in ca 45 genera (depending on taxonomic opinions), divided over five subfamilies. The family includes four groups of genera that are sometimes recogni ...

. It is one of several genera of ferns adapted to an aquatic existence. ''C. richardii'' was previously regarded as being part of the species ''

Ceratopteris thalictroides ''Ceratopteris thalictroides'' is a fern species belonging to the genus ''Ceratopteris'', one of only two genera of the subfamily Parkerioideae of the family Pteridaceae. Common names ''Ceratopteris thalictroides'' is commonly known as water ...

''.

"C-Fern"

This particular species is of special scientific interest because a patented strain, called "C-Fern", was developed as a scientific aid and teaching tool in biology in 1995. The use of "C-Fern" is facilitated by the fact that it grows readily in a cell-culture dish on agar media, reaching sexual maturity within 2–3 weeks of

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, ...

inoculation, with motile sperm cells being visible at this time. Over the course of about 6 weeks

germination Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fe ...

, sex determination and development of

gametophyte A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the ...

fertilization Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Pro ...

embryogenesis An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

organogenesis Organogenesis is the phase of embryonic development that starts at the end of gastrulation and continues until birth. During organogenesis, the three germ layers formed from gastrulation (the ectoderm, endoderm, and mesoderm) form the internal org ...

, and

sporophyte A sporophyte () is the diploid multicellular stage in the life cycle of a plant or alga which produces asexual spores. This stage alternates with a multicellular haploid gametophyte phase. Life cycle The sporophyte develops from the zygote ...

growth can all be observed, allowing an incredibly comprehensive study of the life cycle of homosporous ferns in a relatively short time period. In addition, due to the small size of the plant many specimens can be observed growing simultaneously, allowing for larger sample sizes in research studies. Following the culture of "C-Fern" in dishes it can be transplanted to a dirt substrate, where it can be further allowed to grow and future generations can be used for subsequent studies. Monilophytes are generally studied far less than other groups of plants and a full genome sequence is not yet available, however due to the development of "C-Fern" research into fern biology has been more prevalent and ''C. richardii'' has been used as a model organism to study

vascular plant Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They ...

cell walls,

alternation of generations Alternation of generations (also known as metagenesis or heterogenesis) is the predominant type of life cycle in plants and algae. It consists of a multicellular haploid sexual phase, the gametophyte, which has a single set of chromosomes alt ...

(and associated mutations),

genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar work ...

population dynamics Population dynamics is the type of mathematics used to model and study the size and age composition of populations as dynamical systems. History Population dynamics has traditionally been the dominant branch of mathematical biology, which has a ...

, and the effects of mitotic disrupter

herbicide Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page f ...

s, among other topics. Despite being genetically identical the inoculated spores can give rise to both

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have ...

s and male gametophytes, depending on the secretion of

antheridiogen Antheridiogens are a class of chemicals secreted by fern gametophytes that have "been shown to influence production of male gametangia and thus mating systems in a large number of terrestrial fern species". Antheridiogens are only observed in homos ...

; this phenomenon has been used to study plant

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

s and the cascade of events that leads to

epigenetic In biology, epigenetics is the study of stable phenotypic changes (known as ''marks'') that do not involve alterations in the DNA sequence. The Greek prefix '' epi-'' ( "over, outside of, around") in ''epigenetics'' implies features that are ...

changes in ferns. The ability to switch from bisexual to all male spores may provide an evolutionary advantage by promoting outbreeding. The use of ''C. richardii'' in genetic research studies has been valuable to understanding fern and plant

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

as a whole, and in 2019 "C-fern" became the first homosporous fern to have its genome partially assembled, thus acting as a

reference genome A reference genome (also known as a reference assembly) is a digital nucleic acid sequence database, assembled by scientists as a representative example of the set of genes in one idealized individual organism of a species. As they are assemble ...

to which other ferns can be compared. ''C. richardii'' spores germinated in space in 1999 on shuttle mission

STS-93 STS-93 in 1999 marked the 95th launch of the Space Shuttle, the 26th launch of ''Columbia'', and the 21st night launch of a Space Shuttle. Eileen Collins became the first female shuttle Commander on this flight. Its primary payload was the Chan ...

, making them one of the few plants to be grown in space. C-Fern Development - 1 Week

References

{{Taxonbar, from=Q5063809 Pteridaceae Flora of Asia Aquatic plants Taxa named by Adolphe-Théodore Brongniart Model organisms Plants described in 1823