''Phyllanthus fluitans'', also known as the red root floater, floating spurge, or apple duckweed (although it is neither a spurge or a

duckweed Lemnoideae is a subfamily of flowering aquatic plants, known as duckweeds, water lentils, or water lenses. They float on or just beneath the surface of still or slow-moving bodies of fresh water and wetlands. Also known as bayroot, they arose fr ...

), is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

free floating ''Free Floating'' () is a 2006 Russian comedy film directed by Boris Khlebnikov. Plot The film tells about a 20-year-old guy who lives in a small town in which the only factory is suddenly closed. He works in the market, goes to various discos ...

aquatic plant Aquatic plants, also referred to as hydrophytes, are vascular plants and Non-vascular plant, non-vascular plants that have adapted to live in aquatic ecosystem, aquatic environments (marine ecosystem, saltwater or freshwater ecosystem, freshwater ...

and

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of ...

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

in the

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 ...

Phyllanthaceae Phyllanthaceae is a Family (biology), family of flowering plants in the eudicot Order (biology), order Malpighiales. It is most closely related to the family Picrodendraceae.Kenneth J. Wurdack and Charles C. Davis. 2009. "Malpighiales phylogeneti ...

. This species is one of the only three non-terrestrial species in the

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 ...

Phyllanthus ''Phyllanthus'' is the largest genus in the plant family Phyllanthaceae. Estimates of the number of species in this genus vary widely, from 750David J. Mabberley. 2008. ''Mabberley's Plant-Book.'' third edition (2008). Cambridge University ...

'', with the other species being '' P. leonardianus'' and '' P. felicis''. The generic name comes from

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

meaning leaf or a leaf (φύλλον, phúllon; phyll) flower (ἄνθος, anthos; anthus), and the specific name comes from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

meaning floating or float (fluito; fluitans). It was described in March 1863 by

George Bentham George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...

and

Johannes Müller Argoviensis Johann Müller (9 May 1828 – 28 January 1896) was a Swiss botanist who was a specialist in lichens. He published under the name Johannes Müller Argoviensis to distinguish himself from other naturalists with similar names. Biography Müller ...

Description

The

stem Stem or STEM most commonly refers to: * Plant stem, a structural axis of a vascular plant * Stem group * Science, technology, engineering, and mathematics Stem or STEM can also refer to: Language and writing * Word stem, part of a word respon ...

s are 3 to 5 cm long, with many rootlets emerging from the nodes. The leaves are sessile and are cordate-orbicular (heart shaped), the leaf surface forms a pocket on each side of the

midrib A primary vein, also known as the midrib, is the main vascular structure running through the center of a leaf. The primary vein is crucial for the leaf’s efficiency in photosynthesis and overall health, as it ensures the proper flow of material ...

that traps air and helps plants float on the water. Plants produce 2–4 small white polymerous

actinomorphic Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts. Uncommonly, flowers may have no axis of symmetry at all, typically because their parts are spirall ...

unisexual Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s on a cyme

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

and are nearly 1.5 mm long.

Seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

capsules are depressed-globular in shape and nearly 3 mm wide with six triangular seeds per capsule, 1.7 mm long by 1.1 mm wide. Below the

epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and Subcutaneous tissue, hypodermis. The epidermal layer provides a barrier to infection from environmental pathogens and regulates the ...

there are large cells bulging outwards, with one or two layers of green cells, sometimes slightly elongated perpendicular to the surface constituting something that resembles or is a palisade parenchyma. There are large gaps separated by walls formed from a single thickness of cells that often go from the chlorenchyma to the lower epidermis. Sometimes this epidermis is also covered by a layer of cells elongated tangentially. We can imagine that with a similar morphology and an anatomy which allows the storage of air the plant is able to float and remain horizontal in an aquatic environment. The lower epidermis is devoid of

stoma In botany, a stoma (: stomata, from Greek language, Greek ''στόμα'', "mouth"), also called a stomate (: stomates), is a pore found in the Epidermis (botany), epidermis of leaves, stems, and other organs, that controls the rate of gas exc ...

ta with a few on the upper epidermis. The leaves vary from green to red depending on the light brightness. The leaves are also

hydrophobic In chemistry, hydrophobicity is the chemical property of a molecule (called a hydrophobe) that is seemingly repelled from a mass of water. In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, thu ...

, probably due to the Salvinia effect.

Taxonomy

It was formerly placed in the family

Euphorbiaceae Euphorbiaceae (), the spurge family, is a large family of flowering plants. In English, they are also commonly called euphorbias, which is also the name of Euphorbia, the type genus of the family. Most spurges, such as ''Euphorbia paralias'', ar ...

evident from the common name "floating spurge", along with many other species in the genus ''Phyllanthus'' and ''Phyllanthaceae'' until 1993, when a

maximum parsimony In phylogenetics and computational phylogenetics, maximum parsimony is an optimality criterion under which the phylogenetic tree that minimizes the total number of character-state changes (or minimizes the cost of differentially weighted charact ...

was done and revealed that Euphorbiaceae had several lineages in it, including ''Phyllanthaceae'' and its subsequent taxa. It is also apparently most closely related to '' P. caroliniensis''.

Distribution and habitat

It is native to the

Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its tributary, tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries ...

with its range being in

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

, Brazil,

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

Paraguay Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...

, and northern

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

with the type location being in the Rio Negro

tributary A tributary, or an ''affluent'', is a stream or river that flows into a larger stream (''main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they ...

. It has been seen outside its native range in southern Florida and Mexico (

Tabasco Tabasco, officially the Free and Sovereign State of Tabasco, is one of the Political divisions of Mexico, 32 Federal Entities of Mexico. It is divided into Municipalities of Tabasco, 17 municipalities and its capital city is Villahermosa. It i ...

) being

naturalised Naturalization (or naturalisation) is the legal act or process by which a non-national of a country acquires the nationality of that country after birth. The definition of naturalization by the International Organization for Migration of the ...

where it has invaded. This species’ distribution can also potentially reach

Puerto Rico ; abbreviated PR), officially the Commonwealth of Puerto Rico, is a Government of Puerto Rico, self-governing Caribbean Geography of Puerto Rico, archipelago and island organized as an Territories of the United States, unincorporated territo ...

, Hawaii,

Louisiana Louisiana ( ; ; ) is a state in the Deep South and South Central regions of the United States. It borders Texas to the west, Arkansas to the north, and Mississippi to the east. Of the 50 U.S. states, it ranks 31st in area and 25 ...

, the southern parts of south east states of the US like

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

Alabama Alabama ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South, Deep Southern regions of the United States. It borders Tennessee to the north, Georgia (U.S. state), Georgia to the east, Florida and the Gu ...

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

, and

Mississippi Mississippi ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South regions of the United States. It borders Tennessee to the north, Alabama to the east, the Gulf of Mexico to the south, Louisiana to the s ...

where it has the potential to be problematic

invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

like water fern,

water lettuce ''Pistia'' is a genus of aquatic plants in the arum family, Araceae. It is the sole genus in the tribe ''Pistieae'' which reflects its systematic isolation within the family. The single species it comprises, ''Pistia stratiotes'', is often call ...

and

water hyacinth ''Pontederia crassipes'' (formerly ''Eichhornia crassipes''), commonly known as common water hyacinth, is an aquatic plant native to South America, naturalized throughout the world, and often invasive species, invasive outside its native rang ...

by covering large swaths of stagnant backwater areas. This noxious species may limit or totally block all ambient light penetration to the bottom of the system, which can stunt and potentially kill submersed plants growing below. It has also been recorded in

Panama Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...

Discovery

This species was discovered for the first time by English botanist

Richard Spruce Richard Spruce (10 September 1817 – 28 December 1893) was an English botanist specializing in bryology. One of the great Victorian botanical explorers, Spruce spent 15 years exploring the Amazon from the Andes to its mouth, and was one of t ...

in the Amazon. At the time of discovery, he wrote in his journal:

"Although as far removed from Sahinià (swimming
aquatic fern The order Salviniales (formerly known as the Hydropteridales and including the former Marsileales) is an order of ferns in the class Polypodiopsida. Description Salviniales are all aquatic and differ from all other ferns in being heterosporous, ...
) as the poles are from each other, the ''Phyllanthus fluitans'' looked so similar in its general appearance that I could hardly believe my eyes when I recognized that it belonged to the
flowering plants Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...
. This is one of the many cases that I have encountered of plants which, totally different in the structure of their flowers and their fruits, manage to resemble each other in their devices."

Commercial use

Red Root Floater is grown commercially for use in

aquarium An aquarium (: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. fishkeeping, Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquati ...

s. The plant is known for its red

root In vascular plants, the roots are the plant organ, organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often bel ...

s (hence the

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...

) and the reddish tint the leaves gain when exposed to bright light.

Gallery

File:Hydrophobic leaves of Phyllanthus fluitans.jpg, Hydrophobic properties of Phyllanthus fluitans showing File:New leaf fluitans.jpg, New green leaves File:Phyllanthus fluitan leaves on water.jpg, Phyllanthus fluitans leaves on water File:Phyllanthus fluitans clusters.jpg, Phyllanthus fluitans clusters File:Big leaves Phyllanthus fluitans.jpg, Big leaves due to right conditions File:Illustration of P. fluitans by R. C. (Robert Chodat) used by Herbier Bossier.jpg, Another image of the illustration of P. fluitans by R. C. used by Herbier Bossier

External links

References

{{Taxonbar, from=Q15450326 fluitans Aquatic plants Aquarium plants Flora of Southern America Flora of the Amazon Plants described in 1863 Taxa named by Johannes Müller Argoviensis Taxa named by George Bentham