Echinodorus

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Echinodorus
Den Den.jpg
Echinodorus grisebachii in an aquarium
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
Order: Alismatales
Family: Alismataceae
Genus: Echinodorus
Richard ex Engelmann in A. Gray, 1848

Echinodorus (burhead or Amazon sword plant) is a genus of plants in the family Alismataceae and distributed in the Western Hemisphere from the central United States to Argentina.[1][2] Its scientific name is derived from Ancient Greek echius – rough husk, and doros – 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[edit]

Plants annual or perennial, growing emerse, floating-leaved, or seasonally submerse, leaves glabrous to stellate-pubescent; rhizomes present or absent; stolons absent; corms absent; tubers absent. Roots not septate. Leaves sessile or petiolate; 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, 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 recurved to spreading, herbaceous 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 1; style terminal or lateral. Fruits plump, often longitudinally ribbed, sometimes flattened, rarely abaxially keeled, abaxial wings absent, lateral wings absent, glands often present.[3][4][5]

Cultivation[edit]

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. 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 submerse small plantlets will form instead of flowers. If grown emerse 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.[6][7][8][9]

Many species are popular in the aquarium or pond. The Amazon sword plants are one of the most popular aquarium plants for their attractive form and general hardiness.

Taxonomy[edit]

The genus Baldellia seems to be very closely related. In the latest revision by Karel Rataj,[10] 62 species, 2 subspecies, and 2 varieties are listed. Many cultivars of uncertain taxonomic status are also listed by the aquarium trade.

Species[edit]

As of May 2014, 30 species are accepted by authorities at Kew Royal Botanic Gardens:[11] Included in the list below are names accepted in previous versions but now regarded as synonyms.

  1. Echinodorus angustifolius Rataj - syn of Helanthium bolivianum (Rusby) Lehtonen & Myllys
  2. Echinodorus argentinensis Rataj - syn of Echinodorus grandiflorus (Cham. & Schltdl.) Micheli
  3. Echinodorus aschersonianus Graebn. - syn of Echinodorus uruguayensis Arechav
  4. Echinodorus berteroi (Spreng.) Fassett - from South Dakota to Argentina
  5. Echinodorus bleherae or E. bleheri Rataj - syn of Echinodorus grisebachii Small
  6. Echinodorus bracteatus Micheli - from Nicaragua to Ecuador
  7. Echinodorus cordifolius (L.) Griseb. - from Illinois to Paraguay
  8. Echinodorus cylindricus Rataj - Brazil
  9. Echinodorus decumbens Kasselm. - Brazil
  10. Echinodorus densinervis Somogyi - Brazil
  11. Echinodorus eglandulosus Rataj - Brazil
  12. Echinodorus emersus Lehtonen - Ecuador, Peru, Bolivia
  13. Echinodorus floribundus (Seub.) Seub. - Veracruz to Argentina
  14. Echinodorus gabrielii Rataj - Brazil
  15. Echinodorus glaucus Rataj - Brazil, Bolivia
  16. Echinodorus grandiflorus (Cham. & Schltdl.) Micheli - Brazil, Paraguay, Uruguay, Argentina, Venezuela, Florida
  17. Echinodorus grisebachii Small - from Nicaragua to Brazil
  18. Echinodorus heikobleheri Rataj - Brazil
  19. Echinodorus horizontalis Rataj - from Guyana to Peru
  20. Echinodorus inpai Rataj - Brazil
  21. Echinodorus isthmicus Fassett - syn of Helanthium bolivianum (Rusby) Lehtonen & Myllys
  22. Echinodorus lanceolatus Rataj - Brazil
  23. Echinodorus longipetalus Micheli - from Suriname to Argentina
  24. Echinodorus longiscapus Arechav. - Brazil, Argentina, Paraguay, Uruguay
  25. Echinodorus macrocarpus Rataj - syn of Echinodorus pubescens (Mart. ex Schult.f.) Seub. ex Warm. - Brazil
  26. Echinodorus macrophyllus (Kunth) Micheli - Brazil, Bolivia
  27. Echinodorus major (Micheli) Rataj - Brazil
  28. Echinodorus nymphaeifolius (Griseb.) Buchenau - syn of Albidella nymphaeifolia (Griseb.) Pichon
  29. Echinodorus opacus Rataj - syn of Echinodorus uruguayensis Arechav
  30. Echinodorus osiris Rataj - syn of Echinodorus uruguayensis Arechav
  31. Echinodorus ovalis C.Wright - syn of Echinodorus cordifolius (L.) Griseb
  32. Echinodorus palaefolius (Nees & Mart.) J.F.Macbr. - Nayarit, Minas Gerais
  33. Echinodorus paniculatus Micheli in A.L.P.de Candolle & A.C.P.de Candolle - from Mexico to Argentina
  34. Echinodorus reptilis Lehtonen - Brazil, Argentina, Paraguay
  35. Echinodorus scaber Rataj - from Nicaragua to Paraguay
  36. Echinodorus subalatus (Mart. ex Schult.f.) Griseb. - from Mexico to Paraguay; also Cuba
  37. Echinodorus tenellus (Mart. ex Schult.f.) Buchenau - syn of Helanthium tenellum (Mart. ex Schult.f.) J.G.Sm. in N.L.Britton
  38. Echinodorus trialatus Fassett - Panama, Colombia, Venezuela, Brazil
  39. Echinodorus tunicatus Small - from Costa Rica to Bolivia
  40. Echinodorus uruguayensis Arechav. - Chile, Argentina, Paraguay, Uruguay, Brazil
  41. Echinodorus virgatus (Hook. & Arn.) Micheli - syn of Echinodorus palifolius (Nees & Mart.) J.F.Macbr

References[edit]

  1. ^ Kew World Checklist of Selected Plant Families
  2. ^ Biota of North America Program
  3. ^ Lot H., A. & A. Novelo Retano. 1994. 234. Alismataceae. 6: 3–8. In G. Davidse, M. Sousa Sánchez & A.O. Chater (eds.) Flora Mesoamericana. Universidad Nacional Autónoma de México, México, D. F.
  4. ^ Haynes, R. R. & L.B. Holm-Nielsen. 1994. The Alismataceae. Flora Neotropica 64: 1–112.
  5. ^ Stevens, W. D., C. Ulloa Ulloa, A. Pool & O. M. Montiel. 2001. Flora de Nicaragua. Monographs in systematic botany from the Missouri Botanical Garden 85: i–xlii,.
  6. ^ Caring for Your New Amazon Sword Plant
  7. ^ More Sword Plants
  8. ^ Sword Plants III
  9. ^ The Amazon Swordplant : Origins, Identification and Care
  10. ^ Rataj, Karel (2004) "A New Revision of the Swordplant genus Echinodorus Richard 1848 (Alismataceae)." Aqua: Journal of Ichthyology and Aquatic Biology, Special Publication No. 1.
  11. ^ Kew World Checklist of Selected Plant Families

External links[edit]