Tridens flavus
(L.) Hitchc. · speciesAt a glance
Sources11 archives
Databases and archives Tridens flavus's data was compiled from.
WikipediaWikimedia Foundation2 languages↗
BioWikiNetmultilingual Wikipediamultilingual↗
GBIFGlobal Biodiversity Information Facility7 516 records↗
ENAEuropean Nucleotide Archive · EMBL-EBI9 eDNA detections↗
BOLD SystemsCentre for Biodiversity Genomics11 specimens↗
NCBIUS National Library of Medicinesequences↗
GRIN TaxonomyUSDA-ARSdistribution & uses↗
Open Tree of LifeOpenTreephylogeny backbone↗
CCDBChromosome Counts DB · Tel Aviv U.genome & karyotype↗
PloiDBPloidy Databasegenome & karyotype
GLoBIGlobal Biotic Interactionsbiotic interactions↗Every layer below draws on the sources above — open one to explore it, or use ← → to move between tabs.
Tridens flavus, the purpletop tridens, red top, or greasegrass, is a large, robust perennial bunchgrass native to eastern North America. It widespread throughout its range and is most often found in man-made habitats, such as hay meadows and lawns. The seeds are purple, giving the grass its common name. The seeds are also oily, leading to its other common name, "greasegrass". It reproduces by seed and tillers. The grass is often confused with the similar looking Johnson grass (Sorghum halepense), although it is only distantly related. Tridens flavus is easily distinguished by its short, hairy ligule. It is a larval host to the common wood nymph, crossline skipper, little glassywing, and the Zabulon skipper.The Xerces Society (2016), Gardening for Butterflies: How You Can Attract and Protect Beautiful, Beneficial Insects, Timber Press.
No narrative description available for this taxon yet.
Size & morphology4
Life cycle & reproduction26
Diet & foraging1
Habitat & environment24
Physiology & chemistry26
Uses & economy15
Other traits4
A DNA barcode is a short, standardised stretch of genes that works like a fingerprint — enough to tell one species from another. Below is the molecular trace Tridens flavus has left across the world's sequence archives.
At a glance
★ the standard DNA barcode for this group — the short region actually read to tell this species apart. The rest are extra genes sequenced along the way.
The complete instruction manual Tridens flavus carries — its genome. We read it from three angles — how big it is, how the DNA is packed into chromosomes, and how completely it has been sequenced — and explain how to read each value as you go.
Chromosomes & ploidyhow the DNA is packaged
2n is the full chromosome count in a normal body cell; n is a gamete (egg or sperm), which carries half. Ploidy is how many complete chromosome sets each cell holds — 2× (diploid) is typical for animals, while higher levels (polyploidy) are common in plants. Click any value below to see the underlying records and sources.
2n 402×CCDB · book-fedorov
n 201×CCDB · Cave1958
diploid inferred1×PloiDB · genus-scale
How far back this lineage goes — and how we know. Everything here is measured in Ma, short for “mega-annum”: millions of years ago. The chart reads left to right like a calendar of the Earth, from the deep past on the left to today at the right edgetop to bottom like a core drilled through the Earth, from the deep past at the top down to today at the bottom.
At a glance
When this lineage existed
How to read this: the coloured strip along the bottomdown the left is the geological calendar — the standard epochs (Pliocene, Pleistocene…) every museum uses, shown so you can see which chapter of Earth's history this lineage lived in. This lineage is a young one, so the strip is zoomed in to epochs — the finer subdivisions inside a period. The orange marker is the DNA clock: DNA accumulates mutations at a roughly steady rate, so comparing this species' DNA with its relatives estimates when the lineage split off — independently of any fossil.
Record type7 516 records
Origin
Range
Wildobservation + sensor
Human sightings and records, or camera-trap / sensor detections — someone (or a device) saw or captured the species in the wild.
Museum / Voucheredphysical evidence
Backed by a physical specimen — a herbarium sheet, sample or voucher held in a collection. “Vouchered” means supported by material evidence, not just an observation.
Wildobservation + sensor
Human sightings and records, or camera-trap / sensor detections — someone (or a device) saw or captured the species in the wild.
Holding institutions85 of 123 geolocated
Institutions and collections holding physical, vouchered specimens of this species — click a row to fly to it on the map.
| Institution | Specimens |
|---|---|
| Chongqing Museumlocation not on record | 179 |
| Wuzhou, CN | 158 |
| University of Stellenboschlocation not on record | 74 |
| Fort Worth, US | 73 |
| Saint Louis, US | 62 |
| Bronx, US | 62 |
| Austin, US | 61 |
| Williamsburg, US | 51 |
| International Salmonella Centre (W.H.O.)location not on record | 50 |
| Emporia, US | 45 |
| Columbia, US | 44 |
| Jackson, US | 38 |
| New Haven, US | 35 |
| College Park, US | 34 |
| Jena Microbial Resource Collectionlocation not on record | 33 |
| Ann Arbor, US | 32 |
| Philadelphia, US | 31 |
| Knoxville, US | 26 |
| Chapel Hill, US | 25 |
| BAYLUlocation not on record | 24 |
| DOI/NPS, Mississippi National River & Recreation Arealocation not on record | 22 |
| Allentown, US | 19 |
| US | 18 |
| Millersville, US | 17 |
| Clemson, US | 16 |
| Bloomington, US | 16 |
| Pittsburg, US | 15 |
| Logan, US | 14 |
| Tuscaloosa, US | 13 |
| Miami, US | 13 |
| Madison, US | 13 |
| University of New Hampshirelocation not on record | 12 |
| AUAlocation not on record | 12 |
| Valdosta State Universitylocation not on record | 11 |
| Burlington, US | 11 |
| Norfolk, US | 11 |
| Philadelphia, US | 11 |
| Fayetteville, US | 10 |
| Tampa, US | 10 |
| Dover, US | 9 |
| Flagstaff, US | 8 |
| Lubbock, US | 8 |
| University of Tennessee at Chattanoogalocation not on record | 8 |
| Tall Timbers Research Stationlocation not on record | 8 |
| Auckland, NZ | 7 |
| University of Southern Mississippilocation not on record | 7 |
| GB | 7 |
| EL PASO, US | 7 |
| Bangkok, TH | 7 |
| Lord Fairfax Community Collegelocation not on record | 7 |
| Lincoln, US | 7 |
| Albuquerque, US | 6 |
| San Angelo, US | 6 |
| Canadian Department of Agriculturelocation not on record | 6 |
| Chadron, US | 6 |
| GAlocation not on record | 6 |
| Dekalb, US | 6 |
| Henderson State Universitylocation not on record | 5 |
| James F. Matthews Center for Biodiversity Studieslocation not on record | 5 |
| Claremont, US | 5 |
| Florida Museum of Natural History- Zoology, Paleontology & Paleobotanylocation not on record | 5 |
| Moscow, US | 5 |
| Museum of the Rockieslocation not on record | 5 |
| Mississippi State, US | 5 |
| Riverside, US | 5 |
| Karlsruhe, DE | 5 |
| Kirksville, US | 4 |
| Hudson, US | 4 |
| ASUlocation not on record | 4 |
| Minia, EG | 4 |
| Denver, US | 4 |
| China Agricultural Universitylocation not on record | 3 |
| US | 3 |
| Richmond, US | 3 |
| Phoenix, US | 3 |
| McWane Science Centerlocation not on record | 3 |
| Jefferson City, US | 3 |
| Fairfax, US | 3 |
| Asheville, US | 3 |
| Johnson City, US | 3 |
| Kew, GB | 3 |
| Oskarshamn, SE | 2 |
| Tempe, US | 2 |
| Denton, US | 2 |
| Weymouth Woods Sandhills Nature Preservelocation not on record | 2 |
| Turlock, US | 2 |
| DOI/NPS, Colonial National Historical Parklocation not on record | 2 |
| LINUlocation not on record | 2 |
| New Brunswick, US | 2 |
| Davenport, US | 2 |
| St. Paul, US | 2 |
| DOI/NPS, Selma to Montgomery National Historic Traillocation not on record | 2 |
| xMDC-Clintonlocation not on record | 2 |
| Audubon Society -- Silver Bluff Audubon Center and Sanctuarylocation not on record | 2 |
| Comisión Técnico Consultiva de Coeficientes de Agostaderolocation not on record | 1 |
| Davis, US | 1 |
| Pondicherry, IN | 1 |
| Vancouver, CA | 1 |
| Durham, US | 1 |
| Stephenville, US | 1 |
| DOI/NPS, Little Rock Central High School National Historic Sitelocation not on record | 1 |
| Whitewater, US | 1 |
| Provo, US | 1 |
| Chicago, US | 1 |
| Agriculture and Agri-Food Canadalocation not on record | 1 |
| Northridge, US | 1 |
| University of South Carolina Salkehatchielocation not on record | 1 |
| Texas A&M Universitylocation not on record | 1 |
| Torreón, MX | 1 |
| Durango, MX | 1 |
| Conway, US | 1 |
| Texas Lutheran Universitylocation not on record | 1 |
| Cambridge, US | 1 |
| Macomb, US | 1 |
| Boise, US | 1 |
| Berlin, DE | 1 |
| Pullman, US | 1 |
| Weber State Universitylocation not on record | 1 |
| Grand Junction, US | 1 |
| Washington, US | 1 |
| Moscow State Universitylocation not on record | 1 |
| Mohonk Preservelocation not on record | 1 |
| University of North Carolina at Pembrokelocation not on record | 1 |
Where the DNA of Tridens flavus was picked up in samples of water, soil or air — nobody saw the organism, only its DNA left behind. A trace is a clue that the species was near, not a confirmed sighting.
Signal
Where its DNA was found
How strong is each trace?
Modelled climatemodelled
How to read this: each dot is one detection of this species' DNA in an environmental sample. The confidence meter weighs how many independent studies and places back up the signal — one detection in one study is a hint; many across several studies is solid. Records dated before 2008 (when eDNA methods began) are treated as likely mislabeled and left off the map.