Toronto native plants starting with O: Oclemena acuminata to Oxypolis rigidior

Above: Osmunda regalis (royal fern).

(Updated August 8, 2009).

It's exciting to see how many possibilities for native plant garderners there are in Toronto (something you'd never guess from the average Toronto plant seller, unfortunately.) I've put a link to the relevant entries in this blog where available. I have tried to be as accurate as possible but I'm no expert so any corrections to this list would be appreciated!

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Z

O

• Oclemena acuminata (whorled wood aster). LBJ, P&M (as Aster acuminata), PLANTS.
• Oclemena x blakei (Blake's aster). PLANTS.
• Oclemena nemoralis (bog aster). LBJ, P&M (as Aster nemoralis), PLANTS. More info: DG.
• Oenothera biennis (common evening primrose). LBJ, P&M, PLANTS, PtS. More info: DG.
• Oenothera clelandii (Cleland's evening-primrose). CC rare, NANPS, PLANTS.
• Oenothera fruticosa (sundrops, narrowleaf evening primrose). P&M, PLANTS. More info: DG.
• Oenothera nutans (nodding evening primrose). PLANTS.
• Oenothera oakesiana (Oakes' evening primrose). PLANTS. More info: DG.
• Oenothera parviflora (small-flowered evening primrose). LBJ, P&M, PLANTS. More info: DG.
• Oenothera perennis (little evening primrose). PLANTS. More info: DG.
• Oenothera pilosella (meadow evening primrose). CC rare, LBJ, PLANTS.
• Oenothera villosa (hairy evening primrose). CC rare, PLANTS. More info: DG.
• Oligoneuron album (upland white aster, prairie goldenrod). NANPS (as Solidago ptarmicoides), P&M (as Aster ptarmicoides), PLANTS.
• Oligoneuron houghtonii (Houghton's goldenrod). PLANTS.
• Omalotheca sylvatica (woodland arctic cudweed). LBJ, PLANTS.
• Onoclea sensibilis (sensitive fern), common. Me (High Park, Wilket Creek Park), Banville, LBJ, NANPS, PLANTS. More info: DG.
• Onosmodium bejariense (soft-hair marbleseed). LBJ, PLANTS.
• Onosmodium bejariense var. bejariense (soft-hairy false-gromwell, soft-hair marbleseed). CC rare (as O. molle), PLANTS.
• Onosmodium bejariense var. hispidissimum (shaggy false-gromwell, soft-hair marbleseed). CC rare (as O. molle ssp. hispidissimum), PLANTS.
• Onosmodium molle: see O. bejariense var. bejariense.
• Onosmodium molle ssp. hispidissimum see O. bejariense var. hispidissimum.
• Ophioglossum pusillum (northern adder's tongue). LBJ, PLANTS.
• Opuntia fragilis (brittle prickly pear). LBJ. More info: DG.
• Opuntia humifusa (prickly pear, devil's tongue). CC SAR, LBJ, NANPS, P&M, PLANTS. More info: DG.
• Orchis spectabilis see Galearis spectabilis.
• Orobanche uniflora (one-flowered cancer-root). P&M, PLANTS. More info: DG.
• Orthilia secunda (sidebells wintergreen). P&M (as Pyrola secunda), PLANTS. More info: DG.
• Oryzopsis asperifolia (rough-leaved mountain rice), rare. Banville, PLANTS.
• Oryzopsis racemosa: see Piptatherum racemosum.
• Osmorhiza claytonii (Clayton's sweetroot). LBJ, PLANTS. More info: DG.
• Osmorhiza longistylis (longstyle sweetroot). PLANTS. More info: DG.
• Osmunda cinnamomia (cinnamon fern), uncommon. Banville, LBJ, PLANTS. More info: DG.
• Osmunda claytoniana (interrupted fern), uncommon. Banville, LBJ, PLANTS. More info: DG.
• Osmunda regalis (royal fern), rare. Me (East York), Banville, PLANTS. More info: DG.
• Osmunda regalis var. spectabilis (royal fern). LBJ, PLANTS.
• Ostrya virginiana (eastern hop-hornbeam), common. Banville, LBJ, PLANTS. More info: DG.
• Ostrya virginiana var. virginiana (hop-hornbeam). LBJ, PLANTS.
• Oxalis montana (mountain woodsorrel). P&M, PLANTS. More info: DG.
• Oxalis stricta (yellow woodsorrel). Me (East York), LBJ, P&M, PLANTS. More info: DG.
• Oxypolis rigidior (stiff cowbane). CC rare, LBJ, PLANTS.

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References

• Me: I've seen it myself, in the wild in Toronto.
• Banville: Banville, Diana. Vascular Plants of Metropolitan Toronto 2nd ed.. Toronto: Toronto Field Naturalists, 1994. (Available by mail order from TFN.)
• CCC: Carolinian Canada Coalition's list of Representative Carolinian Species.
• CC rare: Carolinian Canada Coalitions's list of Carolinian Zone Rare Species
• CC SAR: Carolinian Canada Coalition's list Carolinian Species at Risk
• LBJ: Lady Bird Johnson Wildflower Center.
• NANPS: North American Native Plant Society
• P&M: Peterson, Roger Tory and Margaret McKenny. A field guide to wildflowers: Northeastern and northcentral North America. Boston: Houghton Mifflin Company, 1968.
• PLANTS: United States Department of Agriculture PLANTS Database
• PtS: Planting the Seed (PDF): A Guide to Establishing Prairie and Meadow Communities in Southern Ontario

Info

• DG: Dave's Garden.