''Echinodorus'', commonly known as burhead or Amazon sword, is a genus of plants in the family Alismataceae, native to the Western Hemisphere from the central United States to Argentina. Its

scientific name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

is derived from Ancient Greek ' – "rough husk" - and ' – "leathern bottle" - alluding to ovaries, which in some species are armed with persistent styles, forming prickly head of fruit. Some of the species are commonly cultivated in artificial aquatic habitats.

Description

The plants are annual or perennial, growing emersed, floating-leaved, or seasonally submersed, leaves glabrous to stellate-pubescent;

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 ...

present or absent;

stolons In biology, stolons (from Latin '' stolō'', genitive ''stolōnis'' – "branch"), also known as runners, are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external s ...

absent; corms absent; tubers absent. Roots not septate. Leaves sessile or

petiolate Petiole may refer to: *Petiole (botany), the stalk of a leaf, attaching the blade to the stem *Petiole (insect anatomy) In entomology, petiole is the technical term for the narrow waist of some hymenopteran insects, especially ants, bees, a ...

; petioles triangular, rarely terete; blade with translucent markings as dots or lines present or absent, linear to lanceolate to ovate, base attenuate to cordate, margins entire or undulating, apex obtuse to acute. Inflorescences racemes or

panicles A panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a panicle are o ...

, rarely umbels, of 1–18 whorls, erect or decumbent, emersed; bracts coarse, apex obtuse to acute, surfaces smooth or papillose along veins, apex obtuse to acute. Flowers bisexual, subsessile to pedicellate; bracts subtending pedicels, subulate to lanceolate, shorter than to longer than pedicels, apex obtuse to acute; pedicels ascending to recurved; receptacle convex;

sepals A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

recurved to spreading,

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 t ...

to leathery, sculpturing absent; petals white, entire; stamens 9–25; filaments linear, glabrous; pistils 15–250 or more, spirally arranged on convex receptacle, forming head, distinct;

ovules In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the fe ...

1; style terminal or lateral.

Fruits In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particula ...

plump, often longitudinally ribbed, sometimes flattened, rarely abaxially keeled, abaxial wings absent, lateral wings absent, glands often present.

Cultivation

''Echinodorus'' are by nature marsh and bog plants that can grow submersed. Many species are grown in aquariums. They prefer good light and grow best in a deep, nutrient-rich

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (locomotion), the surface over which an organism lo ...

. Most will grow in variable water conditions, though the majority need tropical or sub-tropical temperature ranges. Propagation is by division or by adventitious new plants developing on submerged flowering stems. The larger species make magnificent specimen plants for the larger aquarium, though they may form aerial leaves in good conditions. If the inflorescence forms submersed, small plantlets will form instead of flowers. If grown emersed and kept humid, flowers and seeds will normally readily form. The seeds can be grown in damp sand in warm, damp conditions. Additional CO₂ often helps in strong growth. Many species are popular in the

aquarium An aquarium (plural: ''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. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

or pond. The Amazon sword plants are one of the most popular

plants for their attractive form and general hardiness. A submerged culture system was developed for rapid micropropagation of this commercially important aquarium plant, ‘Amazon sword’ (''Echinodorus'' ‘Indian Red’).

Taxonomy

The genus ''Baldellia'' seems to be very closely related. In the latest revision by

Karel Rataj Karel may refer to: People * Karel (given name) * Karel (surname) * Charles Karel Bouley, talk radio personality known on air as Karel * Christiaan Karel Appel, Dutch painter Business * Karel Electronics, a Turkish electronics manufacturer * Gr ...

, 62 species, 2 subspecies, and 2 varieties are listed. All species of Echinodorus are variable according to hether they are growing emerse or submerged and their growing conditions. In addition they can hybridise in the wild or through artificial means. Many forms have been given subspecific status or as named forms in the

trade. Accoording to aquarists some of these forms persist in all growing conditions.

Species

As of May 2014, 30 species are accepted by authorities at Kew Royal Botanic Gardens:Kew World Checklist of Selected Plant Families
/ref> Included in the list below are names accepted in previous versions but now regarded as synonyms. Echinodorus grisebachii (5)-flower view

#'' Echinodorus angustifolius'' Rataj - syn of ''

Helanthium bolivianum ''Helanthium bolivianum'' is a species of plant in the Alismataceae. It is native to southern Mexico, Central America, the West Indies and South America.Lehtonen, Samuli & Myllys, Leena. 2008. Cladistics 24(2): 228 References External linksp ...

'' (Rusby) Lehtonen & Myllys #'' Echinodorus argentinensis'' Rataj - syn of '' Echinodorus grandiflorus'' (Cham. & Schltdl.) Micheli #'' Echinodorus aschersonianus'' Graebn. - syn of '' Echinodorus uruguayensis'' Arechav #'' Echinodorus berteroi'' (Spreng.) Fassett - from South Dakota to Argentina #''

Echinodorus bleherae ''Echinodorus grisebachii'' or ''Echinodorus amazonicus'' is commonly known as Amazon sword plant, although other plants are also known under this common name. The aquatic plant is cultivated for and used in ponds and artificial aquatic habitats. ...

'' or '' E. bleheri'' Rataj - syn of ''

Echinodorus grisebachii ''Echinodorus grisebachii'' or ''Echinodorus amazonicus'' is commonly known as Amazon sword plant, although other plants are also known under this common name. The aquatic plant is cultivated for and used in ponds and artificial aquatic habitats. ...

'' Small #'' Echinodorus bracteatus'' Micheli - from Nicaragua to Ecuador #'' Echinodorus cordifolius'' (L.) Griseb. - from Illinois to Paraguay #'' Echinodorus cylindricus'' Rataj - Brazil #'' Echinodorus decumbens'' Kasselm. - Brazil #'' Echinodorus densinervis'' Somogyi - Brazil #'' Echinodorus eglandulosus'' Rataj - Brazil #''

Echinodorus emersus ''Echinodorus emersus'' is a species of plant in the family Alismataceae from South America. References Further reading *Lehtonen, Samuli. "Systematics of the Alismataceae—A morphological evaluation." Aquatic Botany 91.4 (2009): 279–290. * ...

'' Lehtonen - Ecuador, Peru,

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

#'' Echinodorus floribundus'' (Seub.) Seub. - Veracruz to Argentina #'' Echinodorus gabrielii'' Rataj - Brazil #'' Echinodorus glaucus'' Rataj - Brazil,

#'' Echinodorus grandiflorus'' (Cham. & Schltdl.) Micheli - Brazil, Paraguay, Uruguay, Argentina, Venezuela, Florida #''

'' Small - from Nicaragua to Brazil #'' Echinodorus heikobleheri'' Rataj - Brazil #'' Echinodorus horizontalis'' Rataj - from

Guyana Guyana ( or ), officially the Cooperative Republic of Guyana, is a country on the northern mainland of South America. Guyana is an indigenous word which means "Land of Many Waters". The capital city is Georgetown. Guyana is bordered by the ...

to Peru #'' Echinodorus inpai'' Rataj - Brazil #'' Echinodorus isthmicus'' Fassett - syn of ''

'' (Rusby) Lehtonen & Myllys #'' Echinodorus lanceolatus'' Rataj - Brazil #'' Echinodorus longipetalus'' Micheli - from

Suriname Suriname (; srn, Sranankondre or ), officially the Republic of Suriname ( nl, Republiek Suriname , srn, Ripolik fu Sranan), is a country on the northeastern Atlantic coast of South America. It is bordered by the Atlantic Ocean to the north ...

to Argentina #'' Echinodorus longiscapus'' Arechav. - Brazil, Argentina, Paraguay, Uruguay #'' Echinodorus macrocarpus'' Rataj - syn of '' Echinodorus pubescens'' (Mart. ex Schult.f.) Seub. ex Warm. - Brazil #''

Echinodorus macrophyllus ''Echinodorus macrophyllus'' is a species of aquatic plants in the Alismataceae. It is native to Brazil and Bolivia. Description Petioles 2 - 3 x longer than the blade, membraneously alate on the base, thin to densely pilose under the blade. ...

'' (Kunth) Micheli - Brazil,

#'' Echinodorus major'' (Micheli) Rataj - Brazil #'' Echinodorus nymphaeifolius'' (Griseb.) Buchenau - syn of '' Albidella nymphaeifolia'' (Griseb.) Pichon #'' Echinodorus opacus'' Rataj - syn of '' Echinodorus uruguayensis'' Arechav #''

Echinodorus osiris ''Echinodorus'', commonly known as burhead or Amazon sword, is a genus of plants in the family Alismataceae, native to the Western Hemisphere from the central United States to Argentina. Its scientific name is derived from Ancient Greek ' – "r ...

'' Rataj - syn of '' Echinodorus uruguayensis'' Arechav #'' Echinodorus ovalis'' C.Wright - syn of '' Echinodorus cordifolius'' (L.) Griseb #''

Echinodorus palaefolius ''Echinodorus palifolius'', also known as Mexican sword plant is an emerged aquatic plant in the Alismataceae. It has a rather odd, discontinuous range, native to Brazil (Minas Gerais and Bahia), Peru, Uruguay, and Mexico ( Nayarit).Macbride, J ...

'' (Nees & Mart.) J.F.Macbr. - Nayarit, Minas Gerais #'' Echinodorus paniculatus'' Micheli in A.L.P.de Candolle & A.C.P.de Candolle - from Mexico to Argentina #'' Echinodorus reptilis'' Lehtonen - Brazil, Argentina, Paraguay #'' Echinodorus scaber'' Rataj - from Nicaragua to Paraguay #'' Echinodorus subalatus'' (Mart. ex Schult.f.) Griseb. - from Mexico to Paraguay; also Cuba #''

Echinodorus tenellus ''Helanthium tenellum'', the pygmy chain sword, is a species of plants in the Alismataceae. It is native to the eastern United States (from Texas to Florida, north to Michigan and Massachusetts), southern Mexico (Chiapas, Veracruz), West Indies ( ...

'' (Mart. ex Schult.f.) Buchenau - syn of '' Helanthium tenellum'' (Mart. ex Schult.f.) J.G.Sm. in N.L.Britton #'' Echinodorus trialatus'' Fassett - Panama,

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

, Venezuela, Brazil #'' Echinodorus tunicatus'' Small - from

Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

#'' Echinodorus uruguayensis'' Arechav. - Chile, Argentina, Paraguay, Uruguay, Brazil #'' Echinodorus virgatus'' (Hook. & Arn.) Micheli - syn of '' Echinodorus palifolius'' (Nees & Mart.) J.F.Macbr

References

External links

''Echinodorus''

Shutting down the chaos engine — or, identifying some problematic Echinodorus (Alismataceae) types

Bibliography

* Lehtonen S and Myllys L. 2008. Cladistic analysis of Echinodorus (Alismataceae): simultaneous analysis of molecular and morphological data. Cladistics 24: 218–239. {{Taxonbar, from=Q596454 Alismataceae genera Aquatic plants