Arkansas

• Arkansas 05001
  816 taxa Open ↗
• Ashley 05003
  1,236 taxa Open ↗
• Baxter 05005
  1,025 taxa Open ↗
• Benton 05007
  1,372 taxa Open ↗
• Boone 05009
  697 taxa Open ↗
• Bradley 05011
  1,145 taxa Open ↗
• Calhoun 05013
  573 taxa Open ↗
• Carroll 05015
  1,039 taxa Open ↗
• Chicot 05017
  440 taxa Open ↗
• Clark 05019
  896 taxa Open ↗

Showing 1,601–1,650 of 2,679 (native).

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  Oenothera villosa Thunb. ssp. villosa Native OEVIV

  hairy evening primrose · Onagraceae 59 counties
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  Oenothera xerogaura W.L. Wagner & Hoch Native OEXE

  Drummond's beeblossom · Onagraceae 1 county
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  Oldenlandia boscii (DC.) Chapm. Native OLBO

  Bosc's mille graines · Rubiaceae 13 counties
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  Oldenlandia corymbosa L. Native OLCO

  flat-top mille graines · Rubiaceae 3 counties
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  Oldenlandia uniflora L. Native OLUN

  clustered mille graines · Rubiaceae 7 counties
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  Oligoneuron album (Nutt.) G.L. Nesom Native OLAL2

  prairie goldenrod · Asteraceae 2 counties
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  Oligoneuron nitidum (Torr. & A. Gray) Small Native OLNI

  shiny goldenrod · Asteraceae 6 counties
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  Oligoneuron riddellii (Frank ex Riddell) Rydb. Native OLRI2

  Riddell's goldenrod · Asteraceae 1 county
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  Oligoneuron rigidum (L.) Small Native OLRI

  stiff goldenrod · Asteraceae 9 counties
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  Oligoneuron rigidum (L.) Small var. rigidum Native OLRIR

  stiff goldenrod · Asteraceae 9 counties
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  Onoclea sensibilis L. Native ONSE

  sensitive fern · Dryopteridaceae 64 counties
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  Onosmodium bejariense DC. ex A. DC. Native ONBE

  soft-hair marbleseed · Boraginaceae 19 counties
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  Onosmodium bejariense DC. ex A. DC. var. bejariense Native ONBEB

  soft-hair marbleseed · Boraginaceae 19 counties
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  Onosmodium bejariense DC. ex A. DC. var. hispidissimum (Mack.) B.L. Turner Native ONBEH

  softhair marbleseed · Boraginaceae 1 county
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  Onosmodium bejariense DC. ex A. DC. var. occidentale (Mack.) B.L. Turner Native ONBEO

  western marbleseed · Boraginaceae 7 counties
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  Onosmodium bejariense DC. ex A. DC. var. subsetosum (Mack. & Bush) B.L. Turner Native ONBES

  softhair marbleseed · Boraginaceae 14 counties
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  Ophioglossum crotalophoroides Walter Native OPCR

  bulbous adderstongue · Ophioglossaceae 28 counties
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  Ophioglossum crotalophoroides Walter var. crotalophoroides Native OPCRC

  bulbous adderstongue · Ophioglossaceae 28 counties
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  Ophioglossum engelmannii Prantl Native OPEN

  limestone adderstongue · Ophioglossaceae 20 counties
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  Ophioglossum nudicaule L. f. Native OPNU

  least adderstongue · Ophioglossaceae 4 counties
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  Ophioglossum petiolatum Hook. Native OPPE2

  longstem adderstongue · Ophioglossaceae 4 counties
• 
  Ophioglossum vulgatum L. Native OPVU

  southern adderstongue · Ophioglossaceae 22 counties
• 
  Oplismenus hirtellus (L.) P. Beauv. ssp. setarius (Lam.) Mez ex Ekman Native OPHIS

  basketgrass · Poaceae 12 counties
• 
  Opuntia humifusa (Raf.) Raf. Native OPHU

  devil's-tongue · Cactaceae 42 counties
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  Opuntia macrorhiza Engelm. Native OPMA2

  twistspine pricklypear · Cactaceae 14 counties
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  Opuntia macrorhiza Engelm. var. macrorhiza Native OPMAM3

  twistspine pricklypear · Cactaceae 14 counties
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  Opuntia pusilla (Haw.) Haw. Native OPPU2

  cockspur pricklypear · Cactaceae 1 county
• 
  Orbexilum onobrychis (Nutt.) Rydb. Native ORON

  French-grass · Fabaceae 2 counties
• 
  Orbexilum pedunculatum (Mill.) Rydb. Native ORPE

  Sampson's snakeroot · Fabaceae 46 counties
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  Orbexilum pedunculatum (Mill.) Rydb. var. pedunculatum Native ORPEP2

  Sampson's snakeroot · Fabaceae 46 counties
• 
  Orbexilum simplex (Nutt. ex Torr. & A. Gray) Rydb. Native ORSI

  singlestem leather-root · Fabaceae 12 counties
• 
  Orobanche uniflora L. Native ORUN

  oneflowered broomrape · Orobanchaceae 14 counties
• 
  Osmorhiza claytonii (Michx.) C.B. Clarke Native OSCL

  Clayton's sweetroot · Apiaceae 1 county
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  Osmorhiza longistylis (Torr.) DC. Native OSLO

  longstyle sweetroot · Apiaceae 28 counties
• 
  Osmunda cinnamomea L. Native OSCI

  cinnamon fern · Osmundaceae 51 counties
• 
  Osmunda cinnamomea L. var. cinnamomea Native OSCIC

  cinnamon fern · Osmundaceae 1 county
• 
  Osmunda claytoniana L. Native OSCL2

  interrupted fern · Osmundaceae 2 counties
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  Osmunda regalis L. Native OSRE

  royal fern · Osmundaceae 54 counties
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  Osmunda regalis L. var. spectabilis (Willd.) A. Gray Native OSRES

  royal fern · Osmundaceae 54 counties
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  Ostrya virginiana (Mill.) K. Koch Native OSVI

  hophornbeam · Betulaceae 70 counties
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  Oxalis corniculata L. Native OXCO

  creeping woodsorrel · Oxalidaceae 33 counties
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  Oxalis dillenii Jacq. Native OXDI2

  slender yellow woodsorrel · Oxalidaceae 13 counties
• 
  Oxalis stricta L. Native OXST

  common yellow oxalis · Oxalidaceae 69 counties
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  Oxalis violacea L. Native OXVI

  violet woodsorrel · Oxalidaceae 63 counties
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  Oxypolis rigidior (L.) Raf. Native OXRI

  stiff cowbane · Apiaceae 18 counties
• 
  Packera anonyma (Alph. Wood) W.A. Weber & Á. Löve Native PAAN6

  Small's ragwort · Asteraceae 1 county
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  Packera aurea (L.) Á. Löve & D. Löve Native PAAU3

  golden ragwort · Asteraceae 16 counties
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  Packera glabella (Poir.) C. Jeffrey Native PAGL17

  butterweed · Asteraceae 56 counties
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  Packera obovata (Muhl. ex Willd.) W.A. Weber & Á. Löve Native PAOB6

  roundleaf ragwort · Asteraceae 47 counties
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  Packera plattensis (Nutt.) W.A. Weber & Á. Löve Native PAPL12

  prairie groundsel · Asteraceae 19 counties