| Name | Description |
|---|---|
| occulta |
hidden |
| odorata |
fragrant,scented |
| odoratus |
fragrant,scented |
| odorus |
fragrant,scented |
| officinalis |
sold as an herb; medicinal |
| orbicularis |
circular |
| orbiculatus |
circular |
| orbiculus |
circular |
| oreophila |
mountain loving |
| oreophilum |
mountain loving |
| osteosperma |
bony seed |
| osteospermus |
bony seed |
| oxy- |
prefix meaning "sharp, pointed" |
| pachy- |
prefix meaning "thick" |
| pallida |
pale |
| pallidum |
pale |
| palmatum |
hand like |
| palmatus |
hand like |
| paludosa |
marshy |
| paludosus |
marshy |
| parvi- |
prefix meaning "small" |
| patens |
spreading |
| patula |
spreading |
| pauci- |
prefix meaning "few" |
| pauciramosa |
few branches |