Cr
- Crassula — pygmyweeds
- Crassula aquatica — water pygmyweed
- Crataegus — hawthorns
- Crataegus apiomorpha
- Crataegus beata
- Crataegus brainerdii — Brainerd's hawthorn
- Crataegus calpodendron — pear hawthorn
- Crataegus chrysocarpa var. aboriginum
- Crataegus chrysocarpa var. chrysocarpa — fireberry hawthorn, roundleaf hawthorn
- Crataegus chrysocarpa var. phoenicea
- Crataegus coccinea var. coccinea — scarlet hawthorn
- Crataegus coccinea var. fulleriana — Fuller's hawthorn
- Crataegus cognata — white-anthered frosted hawthorn
- Crataegus comptacta
- Crataegus crus-galli — cockspur hawthorn
- Crataegus dilatata
- Crataegus dissona
- Crataegus dodgei var. dodgei — Dodge's hawthorn
- Crataegus dodgei var. flavida
- Crataegus douglasii — black hawthorn, Douglas' hawthorn
- Crataegus flabellata — fanleaf hawthorn, Bosc's thorn, New England hawthorn
- Crataegus formosa
- Crataegus irrasa — unshorn thorn, Blanchard's thorn
- Crataegus lumaria
- Crataegus macracantha — longthorn hawthorn, largethorn hawthorn
- Crataegus macrosperma — bigfruit hawthorn, variable thorn
- Crataegus magniflora
- Crataegus margeretta
- Crataegus mollis — downy hawthorn, red haw
- Crataegus pennsylvanica
- Crataegus perjucunda — Middlesex frosted hawthorn
- Crataegus persimilis — plumleaf hawthorn
- Crataegus populnea
- Crataegus pringlei — Pringle's hawthorn
- Crataegus pruinosa var. parvula
- Crataegus pruinosa var. pruinosa — waxy-fruit hawthorn, frosted hawthorn
- Crataegus punctata — dotted hawthorn
- Crataegus rugosa — broadleaf frosted hawthorn
- Crataegus scabrida
- Crataegus schuettei — royal hawthorn
- Crataegus submollis — Québec hawthorn, Emerson's hawthorn
- Crataegus suborbiculata — Caughuawaga hawthorn
- Crataegus succulenta — fleshy hawthorn, longspine hawthorn
- Crataegus tenax
- Cryptogramma — rockbrakes
- Cryptogramma acrostichoides — American rockbrake, parsleyfern, mountain parsley
- Cryptogramma stelleri — Steller's rockbrake, slender cliffbrake, fragile rockbrake
- Cryptotaenia — honeworts
- Cryptotaenia canadensis — Canada honewort
Read more about this topic: List Of Canadian Plants By Genus C