Today's crossword topic is flowers:
Across
- Daffodils, erica, dogbane, ursi, candytuft and tithonia.
- Daphne, eustoma, dianthus, orchid, ixia and dietes.
Down
- Alstroemeria, dianella and day.
- Ursinias and petunia.
Hints
The tags letters and acrostic don’t truly apply, but they might help your thought process.
I'm pretty sure that $f = 6$.
The values for each box aren't quite letters.
Today's entry is number .1269994261.