What Does the Title Mean?

Here are some passages expounding on this concept:

Florilegia: anthology. The Greek word anthos, "flower," provides the literal sense of the word: a collection of flowers. Anthologies (once also called florilegia, Latin for "a collection of flowers") were originally conceived as collections of "beauties."
--- Jack Lynch, The Guide to Literary Terms (1999)



Florilegia (Latin, florilegium, an anthology) are systematic collections of excerpts (more or less copious) from the works of the Fathers and other ecclesiastical writers of the early period, compiled with a view to serve dogmatic or ethical purposes. . . . Two classes of Christian florilegia may here be distinguished: the dogmatic and the ascetical, or ethical.

. . . .

The ascetical florilegia are collections of moral sentences and excerpts drawn partly from the Scriptures and partly from the Fathers, on such topics as virtues and vices, duties and exercises of a religious life, faith, discipline, etc. . . . An extensive Christian florilegium of the sixth century, entitled tà ‘ierá (Sacred Things), is probably the earliest of these anthologies.
--- Thomas Oestereich, “Fidelis servus et prudens, quem constituit Dominus super familiam suam,” Catholic Encyclopedia, vol. VI (1909)



And, last but not least:

In the thirteenth and fourteenth centuries fairies in England were fond of adding to their magic, exhortations to random collections of Christian saints. Fairies were baffled by Christian doctrine, but they were greatly attracted to saints, whom they saw as powerful magical beings whose patronage it was useful to have. These exhortations were called florilegia (literally, cullings or gatherings of flowers) and fairies taught them to their Christian masters. When the Protestant religion took hold in England and saints fell out of favour, florilegia degenerated into meaningless collections of magical words and bits of other spells, thrown in by the magician in the hope that some of them might take effect.
--- Susanna Clarke, Jonathan Strange & Mr Norrell 807 n.3 (2004)