Oenothera speciosa, 182.
taraxacifolia, 183.
Omphalodes verna, 185.
Ononis rotundifolia, 185.
Onosma taurica, 187.
Orchis, brown, 189.
foliosa, 189.
fusca, 189.
Orchis, leafy, 189.
militaris, 189.
soldier or brown man, 189.
Origanum pulchellum, 191.
Orobus vernus, 192.
Oswego tea, 175.
Ourisia coccinea, 193.
Oxlips, 211.