The most common and most likely answer to this crossword clue is the 8 letter word EPIPHYTE
E
P
I
P
H
Y
T
E
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The straight part
We know that "In-plant" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in-plant = epiphyte.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 EPIPHYTE mean?
EPIPHYTE noun- A plant that grows on another, using it for physical support but obtaining no nutrients from it and neither causing damage nor offering benefit; an air plant.