List of Canadian plants by family O

Main page: List of Canadian plants by family

This is a dynamic list and may never be able to satisfy particular standards for completeness. You can help by expanding it with reliably sourced entries.

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Oedipodiaceae

• Oedipodium griffithianum

Oleaceae

Fraxinus americana — white ash Fraxinus latifolia — Oregon ash Fraxinus nigra — black ash

Fraxinus pennsylvanica — green ash Fraxinus profunda — pumpkin ash Fraxinus quadrangulata — blue ash

Onagraceae

Boisduvalia densiflora — denseflower spike-primrose Boisduvalia glabella — smooth spike-primrose Calylophus serrulatus — yellow evening-primrose Camissonia andina — Blackfoot River suncup Camissonia breviflora — shortflower suncup Camissonia contorta — dwarf contorted suncup Circaea alpina — small enchanter's-nightshade Circaea lutetiana — southern broadleaf enchanter's-nightshade Circaea x intermedia — intermediate enchanger's-nightshade Clarkia amoena — farewell-to-spring Clarkia pulchella — largeflower clarkia Clarkia purpurea — winecup clarkia Clarkia rhomboidea — tongue clarkia Epilobium anagallidifolium — alpine willowherb Epilobium angustifolium — fireweed Epilobium arcticum — arctic willowherb Epilobium brachycarpum — panicled willowherb Epilobium ciliatum — hairy willowherb Epilobium clavatum — clavate-fruit willowherb Epilobium coloratum — purpleleaf willowherb Epilobium davuricum — Dahuria willowherb Epilobium foliosum — California willowherb Epilobium glaberrimum — glaucous willowherb Epilobium halleanum — glandular willowherb Epilobium hornemannii — Hornemann's willowherb Epilobium lactiflorum — whiteflower willowherb Epilobium latifolium — river beauty Epilobium leptocarpum — slender-fruited willowherb Epilobium leptophyllum — linear-leaved willowherb

Epilobium luteum — yellow willowherb Epilobium minutum — smallflower willowherb Epilobium mirabile — Olimple Mountain willowherb Epilobium oregonense — Oregon willowherb Epilobium palustre — marsh willowherb Epilobium saximontanum — Rocky Mountain willowherb Epilobium strictum — downy willowherb Epilobium x wisconsinense Gaura biennis — biennial gaura Gaura coccinea — scarlet gaura Gayophytum diffusum — diffuse groundsmoke Gayophytum humile — low groundsmoke Gayophytum racemosum — racemed groundsmoke Gayophytum ramosissimum — much-branch groundsmoke Ludwigia alternifolia — bushy seedbox Ludwigia palustris — marsh seedbox Ludwigia polycarpa — many-fruit false-loosestrife Oenothera biennis — common evening-primrose Oenothera caespitosa — tufted evening-primrose Oenothera clelandii — lesser four-point evening-primrose Oenothera elata — Hooker's evening-primrose Oenothera flava — long-tubed evening-primrose Oenothera fruticosa — narrowleaf sundrops Oenothera nuttallii — white-stemmed evening-primrose Oenothera oakesiana — Oakes' evening-primrose Oenothera pallida — pale evening-primrose Oenothera parviflora — northern evening-primrose Oenothera perennis — small sundrops Oenothera pilosella — meadow evening-primrose Oenothera villosa — hairy evening-primrose

Ophioglossaceae

Botrychium acuminatum — moonwort Botrychium ascendens — upward-lobed moonwort Botrychium boreale — northern moonwort Botrychium campestre — prairie dunewort Botrychium crenulatum — crenulate moonwort Botrychium dissectum — cutleaf grapefern Botrychium hesperium — western moonwort Botrychium lanceolatum — triangle grapefern Botrychium lineare — narrowleaf grapefern Botrychium lunaria — moonwort grapefern Botrychium matricariifolium — chamomile grapefern Botrychium minganense — Mingan's moonwort Botrychium montanum — mountain moonwort Botrychium mormo — little goblin moonwort Botrychium multifidum — leathery grapefern

Botrychium oneidense — bluntlobe grapefern Botrychium pallidum — pale moonwort Botrychium paradoxum — peculiar moonwort Botrychium pedunculosum — stalked moonwort Botrychium pinnatum — northern moonwort Botrychium pseudopinnatum — false daisyleaf grapefern Botrychium rugulosum — rugulose grapefern Botrychium simplex — least grapefern Botrychium spathulatum — spoonleaf moonwort Botrychium tunux Botrychium virginianum — rattlesnake fern Botrychium x watertonense Botrychium yaaxudakeit Ophioglossum pusillum — northern adder's-tongue Ophioglossum vulgatum — southern adder's-tongue

Orchidaceae

Amerorchis rotundifolia — round-leaved orchis Aplectrum hyemale — puttyroot Arethusa bulbosa — dragon's mouth Calopogon tuberosus — tuberous grass-pink Calypso bulbosa — fairy slipper Cephalanthera austiniae — phantom orchid Coeloglossum viride — longbract green orchis Corallorhiza maculata — spotted coralroot Corallorhiza mertensiana — Merten's coralroot Corallorhiza odontorhiza — autumn coralroot Corallorhiza striata — striped coralroot Corallorhiza trifida — early coralroot Cypripedium acaule — pink lady's-slipper Cypripedium arietinum — ram's-head lady's-slipper Cypripedium candidum — small white lady's-slipper Cypripedium guttatum — spotted lady's-slipper Cypripedium montanum — mountain lady's-slipper Cypripedium parviflorum — American yellow lady's-slipper Cypripedium passerinum — sparrow's-egg lady's-slipper Cypripedium reginae — showy lady's-slipper Cypripedium x andrewsii — Andrews' lady's-slipper Cypripedium x columbianum — Columbian lady's-slipper Cypripedium x favillianum Cypripedium x landonii — Landon's lady's-slipper Dactylorhiza praetermissa — southern marsh orchid Epipactis gigantea — giant helleborine Galearis spectabilis — showy orchis Goodyera oblongifolia — giant rattlesnake-plantain Goodyera pubescens — downy rattlesnake-plantain Goodyera repens — dwarf rattlesnake-plantain Goodyera tesselata — checkered rattlesnake-plantain Isotria medeoloides — small whorled pogonia Isotria verticillata — large whorled pogonia Liparis liliifolia — large twayblade Liparis loeselii — Lösel's twayblade Malaxis brachypoda — white adder's-mouth Malaxis diphyllos — Aleutian adder's-mouth Malaxis paludosa — bog adder's-mouth Malaxis unifolia — green adder's-mouth Neottia auriculata — auricled twayblade Neottia australis — southern twayblade Neottia borealis — northern twayblade Neottia caurina — western twayblade Neottia convallarioides — broad-leaved twayblade

Neottia cordata — heartleaf twayblade Neottia x veltmanii — Veltman's twayblade Piperia candida — white piperia Piperia elegans — hillside rein orchid Piperia elongata — denseflower rein orchid Piperia transversa — royal rein orchid Piperia unalascensis — Alaska rein orchid Platanthera albida — vanilla-scent bog orchid Platanthera aquilonis Platanthera blephariglottis — white-fringe orchis Platanthera chorisiana — Choriso bog orchid Platanthera clavellata — small green woodland orchid Platanthera dilatata — leafy white orchis Platanthera flava — southern rein orchid Platanthera grandiflora — large purple-fringe orchis Platanthera hookeri — Hooker's orchis Platanthera hyperborea — leafy northern green orchid Platanthera lacera — green-fringe orchis Platanthera leucophaea — eastern prairie white-fringed orchid Platanthera leucostachys — Bog rein orchid, scentbottle Platanthera obtusata — small northern bog orchid Platanthera orbiculata — large roundleaf orchid Platanthera praeclara — western prairie white-fringed orchid Platanthera psycodes — small purple-fringe orchis Platanthera stricta — slender bog orchid Platanthera x andrewsii — Andrews' platanthera Platanthera x hollandiae — Holland's platanthera Platanthera x keenanii — Keenan's platanthera Platanthera x media Platanthera x reznicekii — Reznicek's platanthera Platanthera x vossii — Voss' platanthera Pogonia ophioglossoides — rose pogonia Spiranthes casei — Case's ladies'-tresses Spiranthes cernua — nodding ladies'-tresses Spiranthes lacera — southern slender ladies'-tresses Spiranthes lucida — shining ladies'-tresses Spiranthes magnicamporum — Great Plains ladies'-tresses Spiranthes ochroleuca — yellow nodding ladies'-tresses Spiranthes ovalis — lesser ladies'-tresses Spiranthes romanzoffiana — hooded ladies'-tresses Spiranthes x intermedia Spiranthes x simpsonii — Simpson's ladies'-tresses Triphora trianthophora — nodding pogonia

Orobanchaceae

Boschniakia hookeri — Vancouver groundcone Boschniakia rossica — northern groundcone Boschniakia strobilacea — California groundcone Conopholis americana — American cancer-root Epifagus virginiana — beechdrops Orobanche californica — California broomrape

Orobanche corymbosa — flat-top broomrape Orobanche fasciculata — clustered broomrape Orobanche ludoviciana — Louisiana broomrape Orobanche pinorum — pine broomrape Orobanche uniflora — one-flowered broomrape

Orthotrichaceae

Amphidium californicum Amphidium lapponicum Amphidium mougeotii Drummondia prorepens Orthotrichum affine Orthotrichum alpestre Orthotrichum anomalum Orthotrichum consimile Orthotrichum cupulatum Orthotrichum gymnostomum Orthotrichum hallii Orthotrichum laevigatum Orthotrichum lyellii Orthotrichum obtusifolium — blunt bristle-moss Orthotrichum ohioense Orthotrichum pallens Orthotrichum pellucidum Orthotrichum pulchellum Orthotrichum pumilum Orthotrichum pusillum Orthotrichum pylaisii

Orthotrichum rivulare Orthotrichum rupestre Orthotrichum sordidum Orthotrichum speciosum Orthotrichum stellatum Orthotrichum stramineum Orthotrichum strangulatum Orthotrichum striatum Orthotrichum tenellum Ulota coarctata Ulota crispa Ulota curvifolia Ulota drummondii Ulota hutchinsiae Ulota megalospora Ulota obtusiuscula Ulota phyllantha Zygodon conoideus Zygodon gracilis Zygodon reinwardtii Zygodon viridissimus

Osmundaceae

Osmunda claytoniana — interrupted fern

Osmunda spectabilis — royal fern Osmundastrum cinnamomeum — cinnamon fern

Oxalidaceae

Oxalis dillenii — Dillen's woodsorrel Oxalis montana — white woodsorrel Oxalis oregana — Oregon woodsorrel

Oxalis stricta — common yellow woodsorrel Oxalis suksdorfii — western yellow oxalis