The most common and most likely answer to this crossword clue is the 7 letter word LABELLA
L
A
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L
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Buddy explains!
The straight part
We know that "Orchid petals" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case orchid petals = labella.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does LABELLA mean?
LABELLA noun- The lower central petal of a flower (especially an orchid), usually developed to be showy and attract pollinators.
- Part of the mouth of an insect, especially the sucking mouthparts of a fly.