Shed virtue on the soil, as doth a ray
Of sunlight: but the immortal qualities
By which their races differ, as they once
Differed in blood alive, with various power
Favour the various vegetable germs
With kindred specialty. This herb, I think,
Grows where the Greek hath been. Its beauty shows
A subtle and full knowledge, and betrays
A genius of contrivance. Seest thou how
The fading emerald and azure blent