Identification key for the species treated here:

1. Indument sparse; corolla more or less regularly curved (or in middle part somewhat flatter) ...................................... O. palaestina

– Indument dense; corolla curved basally and on the upper lip, straight in the middle part................................................................. 2

2. Inflorescence dense in all its length; stem usually very robust; bracts usually distinctly longer than the corolla............................... ........................................................................................................................................................................................... O. australis

– Inflorescence dense above, lax below or loosely overall; stem gracile or moderately robust, very rare robust; bracts as long as the corolla or slightly longer .................................................................................................................................................................... 3

3. Indument of the corolla glandular woolly or glandular lanate (that means covered by numerous long curly hairs) .... O. pubescens

– Indument of the corolla short to medium length, straight glandular hairy......................................................................................... 4

4. Basal flowers basally or in the lower third curved; stigma whitish, bright pink, rarely yellowish. On Asteraceae ............................. ........................................................................................................................................................................................ O. canescens

– Basal flowers basally or in the lower third geniculate; stigma dark purplish, very rare yellow. Usually on Apiaceae, rarely on Asteraceae, Solanaceae (Digitalis) ............................................................................................................................... O. amethystea