The most common and most likely answer to this crossword clue is the 9 letter word HORSETAIL
I've seen this crossword clue in Independent
H
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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 HORSETAIL mean?
HORSETAIL noun- The tail of a horse.
- Any of various simple vascular plants, of the order Equisetales, that have hollow stems and produce spores.
- A Turkish standard denoting rank.
- A mare's tail, a water plant in genus Hippuris.
- Any waterfall, the descending water of which maintains contact with bedrock most of the time.
- Cauda equina, a bundle of nerve fibers.
- A ponytail hairstyle.