Analysis of With Three Flowers

Herewith I send you three pressed withered flowers:
This one was white, with golden star; this, blue
As Capri's cave; that, purple and shot through
With sunset-orange. Where the Duomo towers
In diamond air, and under pendent bowers
The Arno glides, this faded violet grew
On Landor's grave; from Landor's heart it drew
Its clouded azure in the long spring hours.
Within the shadow of the Pyramid
Of Cais Cestius was the daisy found,
White as the soul of Keats in Paradise.
The pansy -- there were hundreds of them hid
In the thick grass that folded Shelley's mound,
Guarding his ashes with most lovely eyes.