Species Recorded | Taxon | Scientific Name | Common Name | Records | Latest |
| algae or stonewort | Rhizoclonium riparium | an alga | 1 | 2013 |
| amphibian | Rana | a green frog (unidentified) | 20 | 2020 |
| amphibian | Rana sp. or Bufo sp. or Hyla sp. | a frog or a tree frog or a toad (unidentified) | 4 | 2017 |
| amphibian | Rana sp. or Hyla sp. (a frog unidentified) | a frog (unidentified) | 103 | 2019 |
| amphibian | Rana temporaria | Common Frog | 2981 | 2021 |
| ant, bee, wasp, sawfly or ichneumon (and others) | Rhadinoceraea micans | a sawfly | 4 | 2019 |
| ant, bee, wasp, sawfly or ichneumon (and others) | Rhogogaster | a Rhogogaster species (unidentified) | 1 | 2008 |
| ant, bee, wasp, sawfly or ichneumon (and others) | Rhogogaster (Cytisogaster) genistae | a sawfly | 1 | 2000 |
| ant, bee, wasp, sawfly or ichneumon (and others) | Rhogogaster (Cytisogaster) picta | a sawfly | 1 | 2004 |
| ant, bee, wasp, sawfly or ichneumon (and others) | Rhogogaster punctulata | a sawfly | 1 | 2018 |
| ant, bee, wasp, sawfly or ichneumon (and others) | Rhogogaster viridis | a sawfly | 17 | 2018 |
| ant, bee, wasp, sawfly or ichneumon (and others) | Rhopalum (Corynopus) coarctatum | a solitary wasp | 4 | 2001 |
| ant, bee, wasp, sawfly or ichneumon (and others) | Rhopalum (Rhopalum) clavipes | a solitary wasp | 3 | 1997 |
| ant, bee, wasp, sawfly or ichneumon (and others) | Rhyssa persuasoria | an ichneumon wasp | 6 | 2019 |
| beetle | Rhagium (Hagrium) bifasciatum | a longhorn beetle | 8 | 2014 |
| beetle | Rhagium mordax | Black-spotted Longhorn Beetle | 24 | 2019 |
| beetle | Rhagonycha | a Rhagonycha species (unidentified) | 1 | 2017 |
| beetle | Rhagonycha fulva | Common red soldier beetle | 390 | 2019 |
| beetle | Rhagonycha lignosa | a soldier beetle | 39 | 2019 |
| beetle | Rhagonycha limbata | a soldier beetle | 30 | 2019 |
| beetle | Rhagonycha testacea | a soldier beetle | 5 | 2013 |
| beetle | Rhamphus oxyacanthae | a weevil | 5 | 2016 |
| beetle | Rhamphus pulicarius | a weevil | 1 | 2014 |
| beetle | Rhantus | a Rhantus species (unidentified) | 18 | 2012 |
| beetle | Rhantus (Nartus) grapii | a water beetle | 45 | 2018 |
| beetle | Rhantus (Rhantus) frontalis | a water beetle | 1 | 1999 |
| beetle | Rhantus (Rhantus) suturalis | a Beetle | 35 | 2015 |
| beetle | Rhantus (Rhantus) suturalis | a water beetle | 8 | 1999 |
| beetle | Rhinocyllus conicus | a weevil | 14 | 2019 |
| beetle | Rhinoncus bruchoides | a weevil | 1 | 2015 |
| beetle | Rhinoncus castor | a weevil | 3 | 2016 |
| beetle | Rhinoncus inconspectus | a weevil | 2 | 2017 |
| beetle | Rhinoncus pericarpius | a weevil | 20 | 2018 |
| beetle | Rhinoncus perpendicularis | a weevil | 6 | 2018 |
| beetle | Rhinusa antirrhini | a weevil | 4 | 2001 |
| beetle | Rhizophagus (Rhizophagus) bipustulatus | a narrow bark beetle | 7 | 2017 |
| beetle | Rhizophagus (Rhizophagus) dispar | a narrow bark beetle | 5 | 2018 |
| beetle | Rhizophagus (Rhizophagus) ferrugineus | a narrow bark beetle | 1 | 2001 |
| beetle | Rhizophagus (Rhizophagus) parallelocollis | Graveyard Beetle | 1 | 1990 |
| beetle | Rhizophagus (Rhizophagus) perforatus | a narrow bark beetle | 1 | 2001 |
| beetle | Rhopalomesites tardyi | a weevil | 11 | 2003 |
| beetle | Rhyzobius chrysomeloides | a ladybird | 9 | 2017 |
| beetle | Rhyzobius litura | a ladybird | 69 | 2018 |
| beetle | Rhyzobius lophanthae | a ladybird | 1 | 2014 |
| beetle | Riolus subviolaceus | a riffle beetle | 1 | 1920 |
| beetle | Rugilus orbiculatus | a rove beetle | 6 | 2018 |
| beetle | Rugilus rufipes | a rove beetle | 1 | 2018 |
| beetle | Rutpela maculata | Spotted Longhorn | 120 | 2020 |
| bird | Rallus aquaticus | Water Rail | 1405 | 2021 |
| bird | Recurvirostra avosetta | Avocet | 416 | 2019 |
| bird | Regulus ignicapilla | Firecrest | 239 | 2019 |
| bird | Regulus regulus | Goldcrest | 6768 | 2021 |
| bird | Remiz pendulinus | Penduline Tit | 2 | 2012 |
| bird | Riparia riparia | Sand Martin | 2105 | 2019 |
| bird | Rissa tridactyla | Kittiwake | 197 | 2019 |
| bug | Ranatra (Ranatra) linearis | Water Stick Insect | 36 | 2020 |
| bug | Reduviidae | a Reduviidae species (unidentified) | 1 | 2018 |
| bug | Reduvius personatus | an assassin bug | 4 | 2019 |
| bug | Rhabdomiris striatellus | a plantbug or grassbug | 18 | 2019 |
| bug | Rhopalosiphum insertum | Apple-Grass Aphid | 39 | 1985 |
| bug | Rhopalosiphum maidis | Cereal Leaf Aphid | 6 | 2008 |
| bug | Rhopalosiphum nymphaeae | Water Lily Aphid | 2 | 2020 |
| bug | Rhopalosiphum padi | Bird Cherry Aphid | 53 | 2018 |
| bug | Rhopalus (Rhopalus) subrufus | a bug | 101 | 2020 |
| bug | Rhyparochromus pini | a ground bug | 15 | 2019 |
| bug | Ribautiana | a Ribautiana species (unidentified) | 1 | 2017 |
| bug | Ribautiana tenerrima (sensu lato) | a leafhopper | 3 | 2009 |
| bug | Ribautiana ulmi | a leafhopper | 2 | 2009 |
| bug | Ribautodelphax angulosa | a planthopper | 1 | 2018 |
| caddis fly | Rhyacophila | a Rhyacophila caddisfly (unidentified) | 1 | 1990 |
| caddis fly | Rhyacophila dorsalis | a caddisfly | 9 | 2018 |
| caddis fly | Rhyacophilidae | a Rhyacophilidae caddisfly (unidentified) | 12 | 2003 |
| diatom | Rhoicosphenia | a Rhoicosphenia species (unidentified) | 1 | 2010 |
| diatom | Rhoicosphenia abbreviata | a diatom | 2 | 2015 |
| false scorpion | Roncocreagris cambridgei | a false scorpion | 1 | 1972 |
| false scorpion | Roncus (Roncus) lubricus | a false scorpion | 2 | 2000 |
| fish | Raja brachyura | Blonde Ray | 1 | 2011 |
| fish | Raja clavata | Thornback Ray | 16 | 2018 |
| fish | Raja microocellata | Small-eyed Ray | 1 | 2009 |
| fish | Raniceps raninus | Lesser Forkbeard | 7 | 2014 |
| fish | Rutilus rutilus | Roach | 100 | 2018 |
| fungus | Radulomyces confluens | a basidiomycete fungus | 22 | 2013 |
| fungus | Radulomyces molaris | a basidiomycete fungus | 4 | 2013 |
| fungus | Radulomyces rickii | a fungus | 2 | 2008 |
| fungus | Ramalina | a Ramalina species (unidentified) | 1 | 2013 |
| fungus | Ramaria | a Ramaria species (unidentified) | 1 | 2012 |
| fungus | Ramaria abietina | a basidiomycete fungus | 2 | 1996 |
| fungus | Ramaria curta | a fungus | 3 | 2008 |
| fungus | Ramaria decurrens | a fungus | 2 | 2008 |
| fungus | Ramaria formosa | a basidiomycete fungus | 3 | 2007 |
| fungus | Ramaria gracilis | a basidiomycete fungus | 2 | 1999 |
| fungus | Ramaria stricta | Upright Coral | 49 | 2019 |
| fungus | Ramariopsis kunzei | a chantarelle | 4 | 2008 |
| fungus | Ramsbottomia asperior | a fungus | 1 | 2000 |
| fungus | Ramularia | a Ramularia species (unidentified) | 1 | 2000 |
| fungus | Ramularia ari | a fungus | 1 | 2012 |
| fungus | Ramularia cupulariae | a fungus | 1 | 1999 |
| fungus | Ramularia didyma | a leaf fungus | 1 | 1997 |
| fungus | Ramularia endophylla | a fungus | 81 | 2013 |
| fungus | Ramularia filaris var. filaris | a fungus | 3 | 2018 |
| fungus | Ramularia gei | a fungus | 1 | 2009 |
| fungus | Ramularia hypochaeridis | a fungus | 1 | 2001 |
| fungus | Ramularia lychnidicola | a leaf fungus | 1 | 2011 |
| fungus | Ramularia lysimachiarum | a fungus | 1 | 2011 |
| fungus | Ramularia montana | a fungus | 1 | 1999 |
| fungus | Ramularia picridis | a fungus | 4 | 2013 |
| fungus | Ramularia primulae | a fungus | 1 | 2008 |
| fungus | Ramularia purpurascens | a fungus | 4 | 2013 |
| fungus | Ramularia rhabdospora | a fungus | 3 | 2013 |
| fungus | Ramularia rosea | a fungus | 2 | 2011 |
| fungus | Ramularia rubella | a leaf fungus | 46 | 2015 |
| fungus | Ramularia scrophulariae | a fungus | 1 | 1998 |
| fungus | Ramularia ulmariae | a fungus | 4 | 2011 |
| fungus | Rectipilus fasciculatus | a fungus | 1 | 2013 |
| fungus | Resinicium bicolor | a basidiomycete fungus | 2 | 1999 |
| fungus | Resupinatus alboniger | a fungus | 6 | 2014 |
| fungus | Resupinatus applicatus | a basidiomycete fungus | 2 | 2000 |
| fungus | Resupinatus trichotis | a basidiomycete fungus | 3 | 1999 |
| fungus | Rhizomarasmius undatus | a basidiomycete fungus | 4 | 2014 |
| fungus | Rhodocollybia butyracea | a basidiomycete fungus | 26 | 2019 |
| fungus | Rhodocollybia butyracea | Butter Cap | 98 | 2014 |
| fungus | Rhodocollybia maculata | Spotted Tough-shank | 36 | 2019 |
| fungus | Rhodocollybia prolixa var. distorta | a basidiomycete fungus | 2 | 1996 |
| fungus | Rhodocybe gemina | a fungus | 7 | 2010 |
| fungus | Rhodocybe melleopallens | a basidiomycete fungus | 2 | 2014 |
| fungus | Rhodocybe popinalis | a basidiomycete fungus | 2 | 2006 |
| fungus | Rhodocybe truncata | a basidiomycete fungus | 5 | 1998 |
| fungus | Rhodotus palmatus | a basidiomycete fungus | 34 | 2019 |
| fungus | Rhopographus filicinus | a fungus | 14 | 2011 |
| fungus | Rhytisma acerinum | Tar-spot Fungus | 136 | 2019 |
| fungus | Rickenella fibula | a basidiomycete fungus | 104 | 2014 |
| fungus | Rickenella setipes | a basidiomycete fungus | 1 | 1999 |
| fungus | Rickenella swartzii | a basidiomycete fungus | 42 | 2014 |
| fungus | Rigidoporus ulmarius | a basidiomycete fungus | 9 | 2010 |
| fungus | Ripartites tricholoma | a basidiomycete fungus | 22 | 2014 |
| fungus | Rosellinia aquila | an ascomycete fungus | 10 | 2013 |
| fungus | Rosellinia mammiformis | an ascomycete fungus | 12 | 2010 |
| fungus | Rosellinia thelena | an ascomycete fungus | 1 | 2015 |
| fungus | Rugosomyces carneus | a basidiomycete fungus | 76 | 2014 |
| fungus | Rugosomyces ionides | a basidiomycete fungus | 5 | 2005 |
| fungus | Russula aeruginea | a russula or milk-cap | 6 | 2005 |
| fungus | Russula albonigra | a russula or milk-cap | 1 | 2005 |
| fungus | Russula alnetorum | a russula or milk-cap | 1 | 2007 |
| fungus | Russula amoenolens | a fungus | 6 | 2009 |
| fungus | Russula anthracina | a fungus | 11 | 2014 |
| fungus | Russula atropurpurea | a russula or milk-cap | 1 | 2000 |
| fungus | Russula atropurpurea | Blackish-purple Russula | 25 | 2014 |
| fungus | Russula aurea | a russula or milk-cap | 1 | 2000 |
| fungus | Russula aurora | a fungus | 1 | 2009 |
| fungus | Russula aurora | a russula or milk-cap | 6 | 2009 |
| fungus | Russula betularum | a russula or milk-cap | 4 | 2001 |
| fungus | Russula brunneoviolacea | a russula or milk-cap | 1 | 1997 |
| fungus | Russula caerulea | a fungus | 9 | 2013 |
| fungus | Russula caerulea | a russula or milk-cap | 38 | 2015 |
| fungus | Russula cessans | a russula or milk-cap | 1 | 2010 |
| fungus | Russula chloroides | a russula or milk-cap | 23 | 2014 |
| fungus | Russula claroflava | Yellow Swamp Russula | 7 | 2007 |
| fungus | Russula cuprea | a fungus | 8 | 2014 |
| fungus | Russula cyanoxantha | Charcoal Burner (The) | 54 | 2014 |
| fungus | Russula decipiens | a russula or milk-cap | 6 | 2009 |
| fungus | Russula delica | Milk-white Russula | 68 | 2013 |
| fungus | Russula densifolia | a russula or milk-cap | 7 | 2013 |
| fungus | Russula emetica | Sickener (The) | 1 | 2014 |
| fungus | Russula emeticella | a russula or milk-cap | 1 | 2005 |
| fungus | Russula exalbicans | a fungus | 1 | 2010 |
| fungus | Russula exalbicans | a russula or milk-cap | 2 | 2000 |
| fungus | Russula faginea | a fungus | 2 | 2010 |
| fungus | Russula farinipes | a russula or milk-cap | 4 | 2012 |
| fungus | Russula fellea | Geranium-scented Russula | 9 | 2013 |
| fungus | Russula foetens | Foetid Russula | 4 | 2000 |
| fungus | Russula fragilis | Fragile Russula | 13 | 2014 |
| fungus | Russula fragilis var. fragilis | a fungus | 10 | 2010 |
| fungus | Russula gigasperma | a fungus | 2 | 2007 |
| fungus | Russula gracillima | a russula or milk-cap | 2 | 2000 |
| fungus | Russula grata | a russula or milk-cap | 2 | 2000 |
| fungus | Russula graveolens | a fungus | 2 | 2009 |
| fungus | Russula grisea | a russula or milk-cap | 1 | 2006 |
| fungus | Russula heterophylla | a russula or milk-cap | 12 | 2010 |
| fungus | Russula insignis | a fungus | 1 | 2014 |
| fungus | Russula integra var. integra | a russula or milk-cap | 2 | 2000 |
| fungus | Russula ionochlora | a russula or milk-cap | 7 | 2014 |
| fungus | Russula lutea | a russula or milk-cap | 2 | 1996 |
| fungus | Russula luteotacta | a russula or milk-cap | 20 | 2010 |
| fungus | Russula maculata | a russula or milk-cap | 2 | 2010 |
| fungus | Russula mariae | a fungus | 1 | 1967 |
| fungus | Russula nauseosa | a russula or milk-cap | 2 | 2007 |
| fungus | Russula nigricans | Blackening Russula | 29 | 2014 |
| fungus | Russula nitida | a russula or milk-cap | 14 | 2010 |
| fungus | Russula nobilis | a russula or milk-cap | 1 | 2000 |
| fungus | Russula nobilis | Beechwood Sickener | 17 | 2014 |
| fungus | Russula ochroleuca | Common Yellow Russula | 100 | 2019 |
| fungus | Russula odorata | a russula or milk-cap | 9 | 2014 |
| fungus | Russula olivacea | a russula or milk-cap | 1 | 1970 |
| fungus | Russula parazurea | Powdery Brittlegill | 38 | 2014 |
| fungus | Russula pectinatoides | a russula or milk-cap | 2 | 2009 |
| fungus | Russula pelargonia | a russula or milk-cap | 1 | 1987 |
| fungus | Russula praetervisa | a fungus | 9 | 2014 |
| fungus | Russula pseudointegra | a russula or milk-cap | 10 | 2009 |
| fungus | Russula puellaris | a russula or milk-cap | 2 | 2010 |
| fungus | Russula queletii | a russula or milk-cap | 11 | 2019 |
| fungus | Russula romellii | a russula or milk-cap | 1 | 2007 |
| fungus | Russula rosea | a russula or milk-cap | 2 | 2000 |
| fungus | Russula sanguinaria | a fungus | 27 | 2014 |
| fungus | Russula sanguinea | a russula or milk-cap | 24 | 2003 |
| fungus | Russula sardonia | a russula or milk-cap | 8 | 2014 |
| fungus | Russula silvestris | a russula or milk-cap | 4 | 2007 |
| fungus | Russula sororia | a russula or milk-cap | 3 | 2006 |
| fungus | Russula subrubens | a fungus | 1 | 2009 |
| fungus | Russula velenovskyi | a russula or milk-cap | 3 | 2007 |
| fungus | Russula versicolor | a russula or milk-cap | 5 | 2014 |
| fungus | Russula vesca | Bare-toothed Russula | 10 | 2008 |
| fungus | Russula violacea | a russula or milk-cap | 1 | 2005 |
| fungus | Russula xerampelina | a russula or milk-cap | 5 | 2008 |
| fungus | Rutstroemia firma | an ascomycete fungus | 4 | 2012 |
| fungus | Rutstroemia firma | Brown Cup | 1 | 2005 |
| fungus | Ruzenia spermoides | an ascomycete fungus | 11 | 2012 |
| lichen | Ramalina canariensis | a lichen | 2 | 2012 |
| lichen | Ramalina farinacea | Shaggy Strap Lichen | 37 | 2018 |
| lichen | Ramalina fastigiata | a lichen | 30 | 2019 |
| lichen | Ramalina lacera | a lichen | 1 | 2010 |
| lichen | Ramalina siliquosa | a lichen | 2 | 1985 |
| lichen | Ramonia interjecta | a lichen | 1 | 1991 |
| lichen | Rhizocarpon geographicum | Map Lichen | 2 | 2016 |
| lichen | Rhizocarpon petraeum | a lichen | 4 | 2011 |
| lichen | Rhizocarpon reductum | a lichen | 13 | 2014 |
| lichen | Rinodina atrocinerea | a lichen | 2 | 1985 |
| lichen | Rinodina bischoffii | a lichen | 4 | 2018 |
| lichen | Rinodina immersa | a lichen | 1 | 2016 |
| lichen | Rinodina oleae | a lichen | 4 | 2002 |
| lichen | Rinodina sophodes | a lichen | 1 | 1996 |
| lichen | Romjularia lurida | a lichen | 7 | 2018 |
| liverwort | Radula complanata | Even Scalewort | 58 | 2019 |
| liverwort | Reboulia hemisphaerica | Hemisphaeric Liverwort | 4 | 1991 |
| liverwort | Riccardia chamedryfolia | Jagged Germanderwort | 3 | 2010 |
| liverwort | Riccia cavernosa | Cavernous Crystalwort | 7 | 2016 |
| liverwort | Riccia fluitans | Floating Crystalwort | 12 | 2016 |
| liverwort | Riccia glauca | Glaucous Crystalwort | 1 | 2019 |
| liverwort | Riccia sorocarpa | Common Crystalwort | 5 | 2020 |
| liverwort | Ricciocarpos natans | Fringed Heartwort | 1 | 2016 |
| mammal | Rattus | a Rattus species (unidentified) | 4 | 2016 |
| mammal | Rattus norvegicus | Brown Rat | 497 | 2020 |
| mammal | Rattus rattus | Black Rat | 16 | 1965 |
| mammal | Rodentia | a rodent (unidentified) | 4 | 2017 |
| mammal - bat | Rhinolophidae | a Horseshoe Bat (unidentified) | 17 | 2017 |
| mammal - bat | Rhinolophus ferrumequinum | Greater Horseshoe Bat | 1990 | 2019 |
| mammal - bat | Rhinolophus hipposideros | Lesser Horseshoe Bat | 2483 | 2020 |
| mayfly | Rhithrogena semicolorata | a mayfly | 2 | 1990 |
| mollusc | Radix auricularia | a pond snail | 3 | 2013 |
| mollusc | Radix balthica | Wandering Snail | 422 | 2018 |
| mollusc | Radix peregra | a pond snail | 15 | 2004 |
| mollusc | Retusa obtusa | a mollusc | 2 | 1976 |
| moss | Racomitrium canescens | Hoary Fringe-moss | 1 | 1990 |
| moss | Racomitrium fasciculare | Green Mountain Fringe-moss | 2 | 2007 |
| moss | Racomitrium lanuginosum | Woolly Fringe-moss | 3 | 1998 |
| moss | Rhizomnium punctatum | Dotted Thyme-moss | 27 | 2019 |
| moss | Rhodobryum roseum | Rose-moss | 2 | 2004 |
| moss | Rhynchostegiella tenella | Tender Feather-moss | 32 | 2018 |
| moss | Rhynchostegiella teneriffae | Teesdale Feather-moss | 1 | 2018 |
| moss | Rhynchostegium confertum | Clustered Feather-moss | 71 | 2019 |
| moss | Rhynchostegium murale | Wall Feather-moss | 13 | 2017 |
| moss | Rhynchostegium riparioides | Long-beaked Water Feather-moss | 9 | 2018 |
| moss | Rhytidiadelphus | a Rhytidiadelphus moss (unidentified) | 7 | 2009 |
| moss | Rhytidiadelphus loreus | Little Shaggy-moss | 4 | 2004 |
| moss | Rhytidiadelphus squarrosus | Springy Turf-moss | 106 | 2019 |
| moss | Rhytidiadelphus triquetrus | Big Shaggy-moss | 55 | 2019 |
| moth or butterfly - macro moth | Rhizedra lutosa | Large Wainscot | 272 | 2018 |
| moth or butterfly - macro moth | Rhodometra sacraria | Vestal | 98 | 2019 |
| moth or butterfly - macro moth | Rhyacia simulans | Dotted Rustic | 11 | 2000 |
| moth or butterfly - macro moth | Rivula sericealis | Straw Dot | 1992 | 2020 |
| moth or butterfly - macro moth | Rusina ferruginea | Brown Rustic | 79 | 2019 |
| moth or butterfly - micro moth | Recurvaria leucatella | a micro-moth | 43 | 2018 |
| moth or butterfly - micro moth | Rhodophaea formosa | a pyralid moth | 15 | 2016 |
| moth or butterfly - micro moth | Rhopobota naevana | Holly Tortrix | 49 | 2019 |
| moth or butterfly - micro moth | Rhyacionia buoliana | Pine Shoot Moth | 14 | 2018 |
| moth or butterfly - micro moth | Rhyacionia pinicolana | a tortrix moth | 6 | 2017 |
| moth or butterfly - micro moth | Rhyacionia pinivorana | Spotted Shoot Moth | 15 | 2020 |
| moth or butterfly - micro moth | Roeslerstammia erxlebella | a micro-moth | 42 | 2017 |
| plant | Ranunculus | a buttercup or water-crowfoot (unidentified) | 183 | 2020 |
| plant | Ranunculus aconitifolius | Aconite-leaved Buttercup | 1 | 1998 |
| plant | Ranunculus acris | Meadow Buttercup | 5660 | 2020 |
| plant | Ranunculus aquatilis | Common Water-crowfoot | 113 | 2018 |
| plant | Ranunculus aquatilis (sensu lato) | a water crowfoot (unidentified) | 23 | 2018 |
| plant | Ranunculus aquatilis (sensu lato) | Water Crowfoot | 40 | 2018 |
| plant | Ranunculus arvensis | Corn Buttercup | 14 | 2013 |
| plant | Ranunculus auricomus | Goldilocks Buttercup | 600 | 2019 |
| plant | Ranunculus (Batrachium) | a Plant | 7 | 2004 |
| plant | Ranunculus baudotii | Brackish Water-crowfoot | 32 | 2016 |
| plant | Ranunculus bulbosus | Bulbous Buttercup | 2568 | 2020 |
| plant | Ranunculus bulbosus var. bulbosus | a buttercup | 1 | 1990 |
| plant | Ranunculus circinatus | Fan-leaved Water-crowfoot | 77 | 2018 |
| plant | Ranunculus ficaria | Lesser Celandine | 3818 | 2021 |
| plant | Ranunculus ficaria subsp. bulbilifer | a lesser celandine | 17 | 2008 |
| plant | Ranunculus ficaria subsp. ficaria | a lesser celandine | 68 | 2013 |
| plant | Ranunculus flammula | Lesser Spearwort | 397 | 2019 |
| plant | Ranunculus fluitans | River Water-crowfoot | 3 | 1998 |
| plant | Ranunculus hederaceus | Ivy-leaved Crowfoot | 7 | 2004 |
| plant | Ranunculus lingua | Greater Spearwort | 86 | 2017 |
| plant | Ranunculus omiophyllus | Round-leaved Crowfoot | 2 | 2003 |
| plant | Ranunculus ophioglossifolius | Adder's-tongue Spearwort | 7 | 2014 |
| plant | Ranunculus parviflorus | Small-flowered Buttercup | 27 | 2017 |
| plant | Ranunculus peltatus | Pond Water-crowfoot | 16 | 2002 |
| plant | Ranunculus penicillatus | Stream Water-crowfoot | 24 | 2016 |
| plant | Ranunculus penicillatus subsp. pseudofluitans | a stream water-crowfoot | 8 | 2016 |
| plant | Ranunculus repens | Creeping Buttercup | 7572 | 2020 |
| plant | Ranunculus sardous | Hairy Buttercup | 4 | 1987 |
| plant | Ranunculus sceleratus | Celery-leaved Buttercup | 747 | 2019 |
| plant | Ranunculus trichophyllus | Thread-leaved Water-crowfoot | 85 | 2015 |
| plant | Ranunculus tripartitus | Three-lobed Water-crowfoot | 2 | 1999 |
| plant | Raphanus raphanistrum | Wild Radish | 242 | 2019 |
| plant | Raphanus raphanistrum subsp. maritimus | Sea Radish | 163 | 2017 |
| plant | Raphanus raphanistrum subsp. raphanistrum | a Plant | 20 | 2016 |
| plant | Raphanus raphanistrum var. raphanistrum | a radish | 1 | 1997 |
| plant | Raphanus sativus | Garden Radish | 7 | 1997 |
| plant | Rapistrum perenne | Steppe Cabbage | 1 | 1933 |
| plant | Rapistrum rugosum | Bastard Cabbage | 16 | 2016 |
| plant | Rapistrum rugosum subsp. linnaeanum | a crucifer | 10 | 1995 |
| plant | Ratibida columnifera | Prairie Coneflower | 2 | 1930 |
| plant | Reseda | a mignonette (unidentified) | 2 | 2009 |
| plant | Reseda lutea | Wild Mignonette | 293 | 2019 |
| plant | Reseda luteola | Weld | 647 | 2019 |
| plant | Rhagadiolus stellatus | a composite | 1 | 1937 |
| plant | Rhamnus alaternus | Mediterranean Buckthorn | 1 | 1955 |
| plant | Rhamnus cathartica | Buckthorn | 722 | 2019 |
| plant | Rheum palmatum x rhaponticum = R. x hybridum | a Plant | 1 | 1955 |
| plant | Rheum palmatum x rhaponticum = R. x hybridum | Rhubarb | 11 | 2019 |
| plant | Rhinanthus minor | Yellow-rattle | 801 | 2019 |
| plant | Rhododendron | A rhododendron (unidentified) | 11 | 2016 |
| plant | Rhododendron ponticum | Rhododendron | 151 | 2018 |
| plant | Rhus | a sumach (unidentified) | 88 | 2009 |
| plant | Rhus typhina | Stag's-horn Sumach | 57 | 2019 |
| plant | Ribes | a currant (unidentified) | 11 | 2019 |
| plant | Ribes nigrum | Black Currant | 123 | 2018 |
| plant | Ribes rubrum | Red Currant | 570 | 2019 |
| plant | Ribes sanguineum | Flowering Currant | 53 | 2019 |
| plant | Ribes uva-crispa | Gooseberry | 823 | 2019 |
| plant | Ridolfia segetum | False Fennel | 1 | 1940 |
| plant | Robinia | a Robinia species (unidentified) | 5 | 2016 |
| plant | Robinia pseudoacacia | False Acacia | 164 | 2018 |
| plant | Rorippa | a water-cress (unidentified) | 10 | 2017 |
| plant | Rorippa amphibia | Greater Yellow-cress | 17 | 2016 |
| plant | Rorippa austriaca | Austrian Yellow-cress | 37 | 2018 |
| plant | Rorippa islandica | Northern Yellow-cress | 3 | 2016 |
| plant | Rorippa microphylla | Narrow-fruited Water-cress | 27 | 2016 |
| plant | Rorippa nasturtium-aquaticum | Water-cress | 320 | 2018 |
| plant | Rorippa nasturtium-aquaticum agg. | Water-cress Spp | 674 | 2016 |
| plant | Rorippa palustris | Marsh Yellow-cress | 99 | 2019 |
| plant | Rorippa sylvestris | Creeping Yellow-cress | 74 | 2019 |
| plant | Rosa | a rose (unidentified) | 2952 | 2020 |
| plant | Rosa agrestis | Small-leaved Sweet-briar | 12 | 2013 |
| plant | Rosa arvensis | Field Rose | 1231 | 2019 |
| plant | Rosa arvensis x canina = R. x irregularis | a rose | 2 | 1991 |
| plant | Rosa arvensis x stylosa = R. x pseudorusticana | a rose | 2 | 1991 |
| plant | Rosa caesia | a rose | 1 | 1995 |
| plant | Rosa caesia glauca x canina | a rose | 1 | 1991 |
| plant | Rosa caesia glauca x stylosa | a rose | 1 | 1991 |
| plant | Rosa caesia subsp. vosagiaca | Glaucous Dog-rose | 2 | 1988 |
| plant | Rosa canina | Dog Rose | 3451 | 2020 |
| plant | Rosa canina agg. | Dog Rose agg. | 1017 | 2020 |
| plant | Rosa canina x caesia = R. x dumalis | a rose | 2 | 2013 |
| plant | Rosa canina x obtusifolia = R. x dumetorum | a rose | 15 | 1993 |
| plant | Rosaceae | a Rosaceae species (unidentified) | 7 | 2012 |
| plant | Rosa ferruginea | Red-leaved Rose | 1 | 2013 |
| plant | Rosa micrantha | Small-flowered Sweet-briar | 32 | 2013 |
| plant | Rosa micrantha x agrestis = R. x bishopii | a rose | 2 | 2011 |
| plant | Rosa multiflora | Many-flowered Rose | 2 | 2019 |
| plant | Rosa obtusifolia | Round-leaved Dog-rose | 1 | 1985 |
| plant | Rosa rubiginosa | Sweet Briar | 30 | 2016 |
| plant | Rosa rubiginosa agg. | Sweet-briar | 14 | 2016 |
| plant | Rosa rugosa | Japanese Rose | 59 | 2018 |
| plant | Rosa sp. cultivar | a cultivated rose | 5 | 2005 |
| plant | Rosa spinosissima | Burnet Rose | 11 | 2016 |
| plant | Rosa stylosa | Short-styled Field-rose | 222 | 2012 |
| plant | Rosa stylosa x agrestis | a rose | 1 | 1995 |
| plant | Rosa stylosa x canina = R. x andegavensis | a rose | 3 | 1988 |
| plant | Rosa tomentosa | Harsh Downy-rose | 31 | 2014 |
| plant | Rosa virginiana | Virginian Rose | 2 | 2013 |
| plant | Rosmarinus officinalis | Rosemary | 48 | 2019 |
| plant | Rostraria cristata | Mediterranean Hair-grass | 1 | 1930 |
| plant | Rubia peregrina | Wild Madder | 430 | 2019 |
| plant | Rubia tinctorum | Madder | 4 | 2015 |
| plant | Rubus | a bramble (unidentified) | 178 | 2020 |
| plant | Rubus adenoleucus | a bramble | 7 | 1999 |
| plant | Rubus adscitus | a bramble | 8 | 1995 |
| plant | Rubus adspersus | a bramble | 7 | 1993 |
| plant | Rubus albionis | a bramble | 13 | 2008 |
| plant | Rubus angusticuspis | a bramble | 8 | 1993 |
| plant | Rubus armeniacus | a bramble | 425 | 2019 |
| plant | Rubus asperidens | a bramble | 21 | 1993 |
| plant | Rubus bartonii | a bramble | 42 | 1996 |
| plant | Rubus bercheriensis | a bramble | 4 | 1989 |
| plant | Rubus bloxamii | a bramble | 2 | 1990 |
| plant | Rubus boraeanus | a bramble | 1 | 1997 |
| plant | Rubus botryeros | a bramble | 2 | 1994 |
| plant | Rubus boudiccae | a bramble | 2 | 1997 |
| plant | Rubus caesius | Dewberry | 820 | 2019 |
| plant | Rubus cardiophyllus | a bramble | 195 | 1999 |
| plant | Rubus cissburiensis | a bramble | 12 | 1995 |
| plant | Rubus cockburnianus | White-stemmed Bramble | 1 | 2014 |
| plant | Rubus conjungens | a bramble | 70 | 1999 |
| plant | Rubus coombensis | a bramble | 1 | 1991 |
| plant | Rubus dasyphyllus | a bramble | 114 | 1999 |
| plant | Rubus dentatifolius | a bramble | 16 | 1999 |
| plant | Rubus divaricatus | a bramble | 1 | 1987 |
| plant | Rubus diversiarmatus | a bramble | 14 | 1996 |
| plant | Rubus diversus | a bramble | 46 | 2008 |
| plant | Rubus eboracensis | a bramble | 56 | 1999 |
| plant | Rubus echinatoides | a bramble | 11 | 1999 |
| plant | Rubus echinatus | a bramble | 142 | 1999 |
| plant | Rubus elegantispinosus | a bramble | 5 | 1991 |
| plant | Rubus errabundus | a bramble | 4 | 1990 |
| plant | Rubus flexuosus | a bramble | 1 | 1989 |
| plant | Rubus formidabilis | a bramble | 1 | 2003 |
| plant | Rubus fruticosus agg. | Bramble | 10482 | 2021 |
| plant | Rubus fruticosus agg. x idaeus | a bramble | 2 | 1999 |
| plant | Rubus fuscicaulis | a bramble | 61 | 1996 |
| plant | Rubus gallofuscus | a bramble | 1 | 1990 |
| plant | Rubus glareosus | a bramble | 11 | 1994 |
| plant | Rubus halsteadensis | a bramble | 2 | 1996 |
| plant | Rubus hibernicus | a bramble | 12 | 1994 |
| plant | Rubus hylocharis | a bramble | 23 | 1999 |
| plant | Rubus idaeus | Raspberry | 711 | 2020 |
| plant | Rubus idaeus x caesius = R. x pseudoidaeus | a bramble | 15 | 1999 |
| plant | Rubus idaeus x vitifolius | Loganberry | 1 | 2014 |
| plant | Rubus imbricatus | a bramble | 66 | 1996 |
| plant | Rubus insectifolius | a bramble | 9 | 1992 |
| plant | Rubus laciniatus | a bramble | 7 | 2016 |
| plant | Rubus lanaticaulis | a bramble | 39 | 1993 |
| plant | Rubus leightonii | a bramble | 5 | 1993 |
| plant | Rubus leyanus | a bramble | 21 | 1992 |
| plant | Rubus lindleianus | a bramble | 121 | 1999 |
| plant | Rubus longithyrsiger | a bramble | 12 | 1994 |
| plant | Rubus longus | a bramble | 29 | 2012 |
| plant | Rubus melanodermis | a bramble | 1 | 1996 |
| plant | Rubus micans | a bramble | 17 | 1999 |
| plant | Rubus moylei | a bramble | 14 | 1994 |
| plant | Rubus murrayi | a bramble | 6 | 1992 |
| plant | Rubus nemoralis | a bramble | 1 | 1991 |
| plant | Rubus nessensis | a bramble | 4 | 1993 |
| plant | Rubus obscuriflorus | a bramble | 4 | 1999 |
| plant | Rubus orbus | a bramble | 2 | 1990 |
| plant | Rubus pampinosus | a bramble | 1 | 1987 |
| plant | Rubus percrispus | a bramble | 57 | 1994 |
| plant | Rubus perdigitatus | a bramble | 3 | 1992 |
| plant | Rubus phoenicolasius | Japanese Wineberry | 11 | 2008 |
| plant | Rubus pictorum | a bramble | 7 | 1993 |
| plant | Rubus polyanthemus | a bramble | 42 | 1993 |
| plant | Rubus prolongatus | a bramble | 5 | 1993 |
| plant | Rubus pruinosus | a bramble | 101 | 1996 |
| plant | Rubus pyramidalis | a bramble | 1 | 1993 |
| plant | Rubus radula | a bramble | 5 | 1992 |
| plant | Rubus raduloides | a bramble | 132 | 2008 |
| plant | Rubus ramosus | a bramble | 1 | 1990 |
| plant | Rubus riddelsdellii | a bramble | 2 | 1994 |
| plant | Rubus rilstonei | a bramble | 1 | 2011 |
| plant | Rubus rossensis | a bramble | 7 | 1992 |
| plant | Rubus rubritinctus | a bramble | 165 | 2008 |
| plant | Rubus rudis | a bramble | 6 | 1990 |
| plant | Rubus rufescens | a bramble | 52 | 1994 |
| plant | Rubus saxatilis | Stone Bramble | 5 | 2007 |
| plant | Rubus scabripes | a bramble | 3 | 1991 |
| plant | Rubus sciocharis | a bramble | 2 | 1989 |
| plant | Rubus scissus | a bramble | 1 | 1987 |
| plant | Rubus spectabilis | Salmonberry | 2 | 1985 |
| plant | Rubus sprengelii | a bramble | 2 | 1993 |
| plant | Rubus subinermoides | a bramble | 5 | 1991 |
| plant | Rubus surrejanus | a bramble | 3 | 1996 |
| plant | Rubus thyrsigeriformis | a bramble | 20 | 2008 |
| plant | Rubus trichodes | a bramble | 10 | 1996 |
| plant | Rubus tricolor | Chinese Bramble | 5 | 2014 |
| plant | Rubus troiensis | a bramble | 21 | 1996 |
| plant | Rubus tuberculatus | a bramble | 260 | 2008 |
| plant | Rubus ulmifolius | a bramble | 1311 | 2019 |
| plant | Rubus ulmifolius x vestitus | a bramble | 1 | 1991 |
| plant | Rubus vagensis | a bramble | 11 | 1996 |
| plant | Rubus vestitus | a bramble | 446 | 2016 |
| plant | Rubus vigorosus | a bramble | 1 | 1991 |
| plant | Rubus villicauliformis | a bramble | 1 | 1990 |
| plant | Rubus winteri | a bramble | 44 | 1997 |
| plant | Rubus wirralensis | a bramble | 87 | 1999 |
| plant | Rumex | a dock (unidentified) | 494 | 2020 |
| plant | Rumex acetosa | Common Sorrel | 2557 | 2020 |
| plant | Rumex acetosa subsp. acetosa | a common sorrel | 1941 | 2006 |
| plant | Rumex acetosa subsp. hibernicus | a common sorrel | 1 | 2002 |
| plant | Rumex acetosella | Sheep's Sorrel [agg.] | 179 | 2019 |
| plant | Rumex acetosella subsp. acetosella | Sheep's Sorrel | 220 | 2019 |
| plant | Rumex alpinus | Monk's Rhubarb | 1 | 1984 |
| plant | Rumex conglomeratus | Clustered Dock | 1227 | 2019 |
| plant | Rumex conglomeratus x obtusifolius = R. x abortivus | a dock | 3 | 2013 |
| plant | Rumex conglomeratus x sanguineus = R. x ruhmeri | a dock | 1 | 1990 |
| plant | Rumex crispus | Curled Dock | 3107 | 2020 |
| plant | Rumex crispus/obtusifolius | a curled dock or broad-leaved dock (unidentified) | 4 | 2016 |
| plant | Rumex crispus subsp. crispus | a curled dock | 226 | 2017 |
| plant | Rumex crispus subsp. littoreus | a curled dock | 13 | 2008 |
| plant | Rumex crispus subsp. uliginosus | Saltmarsh Dock | 8 | 2016 |
| plant | Rumex crispus x conglomeratus = R. x schulzei | a Plant | 1 | 1939 |
| plant | Rumex crispus x obtusifolius = R. x pratensis | a dock | 58 | 2016 |
| plant | Rumex crispus x obtusifolius = R. x pratensis | a Plant | 3 | 2007 |
| plant | Rumex crispus x sanguineus = R. x sagorskii | a dock | 2 | 1992 |
| plant | Rumex cristatus | Greek Dock | 2 | 1995 |
| plant | Rumex cristatus x crispus = R. x dimidiatus | a dock | 1 | 1995 |
| plant | Rumex dentatus | Aegean Dock | 5 | 1939 |
| plant | Rumex frutescens | Argentine Dock | 7 | 2015 |
| plant | Rumex hydrolapathum | Water Dock | 125 | 2016 |
| plant | Rumex maritimus | Golden Dock | 8 | 2018 |
| plant | Rumex obovatus | Obovate-leaved Dock | 1 | 1928 |
| plant | Rumex obtusifolius | Broad-leaved Dock | 4707 | 2020 |
| plant | Rumex obtusifolius var. obtusifolius | a broad-leaved dock | 1 | 1999 |
| plant | Rumex palustris | Marsh Dock | 3 | 2004 |
| plant | Rumex patientia | Patience Dock | 2 | 1987 |
| plant | Rumex pulcher | Fiddle Dock | 221 | 2016 |
| plant | Rumex pulcher x obtusifolius = R. x ogulinensis | a dock | 1 | 1940 |
| plant | Rumex sanguineus | Wood Dock | 3306 | 2020 |
| plant | Rumex sanguineus var. sanguineus | a wood dock | 3 | 2010 |
| plant | Rumex sanguineus x obtusifolius = R. x dufftii | a dock | 8 | 1999 |
| plant | Rumex scutatus | French Sorrel | 5 | 2007 |
| plant | Ruppia cirrhosa | Spiral Tasselweed | 1 | 1991 |
| plant | Ruppia maritima | Beaked Tasselweed | 2 | 1994 |
| plant | Ruscus aculeatus | Butcher's-broom | 100 | 2019 |
| roundworm (nematoda) | Rhabditidae | a Rhabditidae species (unidentified) | 2 | 2009 |
| slime mould | Reticularia | a Reticularia species (unidentified) | 1 | 2011 |
| slime mould | Reticularia intermedia | a slime mould | 1 | 1995 |
| slime mould | Reticularia lycoperdon | a slime mould | 15 | 2018 |
| spider | Robertus lividus | a comb-footed spider | 4 | 1999 |
| spider | Robertus neglectus | a comb-footed spider | 2 | 1965 |
| spider | Rugathodes instabilis | a comb-footed spider | 1 | 1998 |
| tick or mite (acarine) | Riccardoella (Proriccardoella) oudemansi | a slug mite | 1 | 2015 |
| true fly - | Rachispoda breviceps (s. lat., pre 1991) | a lesser dung fly | 2 | 2004 |
| true fly - | Rachispoda limosa | a lesser dung fly | 1 | 2001 |
| true fly - | Rachispoda lutosoidea | a lesser dung fly | 2 | 2004 |
| true fly - | Ramonda spathulata | a parasitic fly | 1 | 2008 |
| true fly - | Reichertella geniculata | a fly | 2 | 2013 |
| true fly - | Renocera pallida | a snail-killing fly | 3 | 2000 |
| true fly - | Rhingia | a Rhingia species (unidentified) | 1 | 2011 |
| true fly - | Rhinophora lepida | a fly | 19 | 2009 |
| true fly - | Rhopalopterum femorale | a fly | 3 | 2009 |
| true fly - cranefly | Rhipidia maculata | a cranefly | 2 | 2001 |
| true fly - (diptera) | Rhipidia maculata | an insect - true fly (Diptera) | 5 | 2009 |
| true fly - (diptera) | Rhypholophus bifurcatus | an insect - true fly (Diptera) | 10 | 2003 |
| true fly - (diptera) | Rhypholophus varius | an insect - true fly (Diptera) | 1 | 2003 |
| true fly - hoverfly | Rhingia campestris | Heineken Hoverfly | 306 | 2020 |
| true fly - hoverfly | Rhingia rostrata | a hoverfly | 7 | 2019 |
| true fly - hoverfly | Riponnensia splendens | a hoverfly | 11 | 2019 |
| true fly - midge, gnat or mosquito | Rabdophaga marginemtorquens | a gall midge | 1 | 1999 |
| true fly - midge, gnat or mosquito | Rabdophaga salicis | a gall midge | 1 | 1999 |
| true fly - midge, gnat or mosquito | Rheotanytarsus | a Rheotanytarsus species (unidentified) | 1 | 2019 |
| true fly - midge, gnat or mosquito | Rondaniola bursaria | a gall midge | 5 | 2012 |
| true fly - midge, gnat or mosquito | Rymosia fasciata | a fungus gnat | 2 | 2003 |
| true fly - midge, gnat or mosquito | Rymosia signatipes | a fungus gnat | 1 | 2001 |
| true fly - midge, gnat or mosquito | Rymosia spinipes | a fungus gnat | 2 | 2003 |
| true fly - picture-winged, conopid or stilt-legged fly | Rhagoletis alternata | a gall fly | 2 | 2018 |
| true fly - robber, empid or dolichopid fly | Rhamphomyia albohirta | a dance fly | 3 | 2003 |
| true fly - robber, empid or dolichopid fly | Rhamphomyia crassirostris | a dance fly | 4 | 2009 |
| true fly - robber, empid or dolichopid fly | Rhamphomyia erythrophthalma | a dance fly | 4 | 2000 |
| true fly - robber, empid or dolichopid fly | Rhamphomyia flava | a dance fly | 3 | 2001 |
| true fly - robber, empid or dolichopid fly | Rhamphomyia longipes | a dance fly | 3 | 2003 |
| true fly - robber, empid or dolichopid fly | Rhamphomyia micropyga | a dance fly | 1 | 2006 |
| true fly - robber, empid or dolichopid fly | Rhamphomyia subcinerascens | a dance fly | 1 | 2013 |
| true fly - robber, empid or dolichopid fly | Rhamphomyia sulcata | a dance fly | 3 | 2001 |
| true fly - robber, empid or dolichopid fly | Rhamphomyia tarsata | a dance fly | 2 | 2009 |
| true fly - robber, empid or dolichopid fly | Rhamphomyia variabilis | a dance fly | 1 | 2001 |
| true fly - robber, empid or dolichopid fly | Rhaphium appendiculatum | a dolichopodid fly | 6 | 2002 |
| true fly - robber, empid or dolichopid fly | Rhaphium caliginosum | a dolichopodid fly | 14 | 2009 |
| true fly - robber, empid or dolichopid fly | Rhaphium consobrinum | a dolichopodid fly | 2 | 2003 |
| true fly - soldier or snipe fly | Rhagio | a Rhagio soldier fly (unidentified) | 1 | 2009 |
| true fly - soldier or snipe fly | Rhagio lineola | Small Fleck-winged Snipefly | 9 | 2018 |
| true fly - soldier or snipe fly | Rhagionidae | a Rhagionidae snipe fly (unidentified) | 2 | 2018 |
| true fly - soldier or snipe fly | Rhagio scolopaceus | Downlooker Snipefly | 59 | 2019 |
| true fly - soldier or snipe fly | Rhagio tringarius | Marsh Snipefly | 35 | 2020 |
| worm | Rhynchobdellae | a Rhynchobdellae species (unidentified) | 1 | 2014 |