Brewer's: Forget-me-nots of the Angels
The stars are so called by Longfellow. The similitude between a little lightblue flower and the yellow stars is very remote. Stars are more like buttercups than forget-me-nots.
Silently, one by one, in the infinite meadows of heaven, Blossom the lovely stars, the forget-me-nots of the angels.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894