| 词条 | Ceratophyllum echinatum |
| 释义 |
|image = |genus = Ceratophyllum |species = echinatum |authority = A. Gray }}Ceratophyllum echinatum, commonly called spineless hornwort, is an aquatic perennial plant of the genus Ceratophyllum.[1] It can be found in ponds and lakes. It is principally an eastern North American species and the only species of its genus endemic to North America.[2] DescriptionCeratophyllum echinatum is an aquatic herb. The spineless hornwort usually does not have any roots with stems that are freely branching (0.3 – 4.0 m long). The leaves are submerged and they are usually in whorls of 5 to 12. Its flowers do not have any petals but have sepals (3 to 15) that are sometimes mistaken for petals. The flower is tiny, could be male or female, and contains about 12 to 16 stamens.[3] It blooms from February to July. The fruits have dry seeds with a lot of spines and a rough surface.[4]DistributionCeratophyllum echinatum can be found in the United States and some parts of Canada.[5]Economic valueIt is often used in aquariums because its appearance, its high oxygen production, and its ability to minimize the blue-green algae growth.{{citation needed|date=December 2014}} Threatened and endangered statusSeveral states list this species as threatened or endangered:[6]
Origin of the nameCeratophyllum comes from the Greek keras, "a horn" and phyllon, "leaf", which is alluding to the stiff and narrow leaf divisions. The specific epithet echinatum comes from echinus which means "sea urchin or hegdehog"; it is therefore called "spiny".[7]References{{Wikispecies}}1. ^{{cite web | url = http://floraofalabama.org/Plant.aspx?id=1488 | title = Ceratophyllum echinatum | work = from Alabama Plant atlas }} {{Taxonbar|from=Q5063798}}2. ^{{cite web | url = http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500338 | title = Ceratophyllum echinatum | work = From Flora of North America }} 3. ^{{cite web | url = http://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Ceratophyllum%20echinatum | title = Species Information | work = Electronic Atlas of the Plants of British Columbia }} 4. ^{{cite web | url = http://wisplants.uwsp.edu/scripts/detail.asp?SpCode=CERECH | title = Ceratophyllum echinatum A.Gray | work = From Robert W. Freckmann Herbarium }} 5. ^{{cite web | url = http://plants.usda.gov/java/profile?symbol=CEEC2 | title = Distribution Map of the Spineless Hornwort | work = From the USDA }} 6. ^{{cite web | url = http://plants.usda.gov/java/profile?symbol=CEEC2 | title = Threatened and Endangered Information | work = From the USDA }} 7. ^{{cite web | url = http://wisplants.uwsp.edu/scripts/detail.asp?SpCode=CERECH | title = Origin of the Name | work = From the Robert W. Freckmann Herbarium }} 4 : Freshwater plants|Plants described in 1847|Flora of North America|Ceratophyllum |
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