بأعلام ياقوت نشرن على رماح من زبرجد
Like ruby banners spread upon emerald spears.
The subject is the red anemone (shaqīq), a single flower. The comparison term is neither a ruby alone nor a spear alone: it is the combined image of bright red banners fixed upon green emerald spears. The relationship between red petals and green stems supplies the visual connection.
This is single-to-composite. The flower counts as one subject, while the coordinated red banners and green spears provide the composite reference. Reducing the likeness to anemone equalling ruby would omit the vivid combination of red and green central to the image.