Bupleurum rotundifolium (hare's ear)

Corallorhiza striata var. striata (hooded coralroot)
Corallorhiza trifida
Corallorhiza trifida (yellow coralroot)
Corallorhiza wisteriana (spring coralroot)
Coreopsis grandiflora (largeflower tickseed)
Coreopsis lanceolata (lanceleaf tickseed)
Coreopsis pubescens (star tickseed)
Coreopsis rosea (pink tickseed)
Coreopsis tinctoria var. tinctoria (golden tickseed)
Coreopsis verticillata (whorled tickseed)
Coriandrum sativum
Corispermum americanum var. rydbergii (American bugseed)
Cornus alba
Cornus amomum (silky dogwood)
Cornus canadensis (bunchberry dogwood)
Cornus drummondii (roughleaf dogwood)
Cornus foemina (stiff dogwood)
Cornus mas
Cornus sanguinea
Cornus suecica (Lapland cornel)
Coronilla varia
Cortinarius
Cortinarius aurilicis
Cortinarius bulliardii
Cortinarius elatior
Cortinarius infractus
Cortinarius orellanoides
Cortinarius orellanus
Cortinarius praestans