The Rarest Ingredient of All

Question

No tricks here- just a riddle this time!

A frog I have been called,
but I have cell walls.
Threatened am I,
but loved am I;
Alone I hang,
no one can find me.

A friend have I,
the forgotten butterfly.
No one can replicate me,
for I am unique:
Free I must be,
for I perish in captivity.
I will dance for you,
for only a week;
If the world does not improve,
my future is bleak.

To differentiate me from others I'll say
the biggest hint of all:
I am of the color gray.
My spooky physique,
the witch, the toad;
"The rarest ingredient of all"
she would have crowed.

More hints than you deserve
you have been given,
so tell me my name-
and make it thrilling!

Answer 1

Are you a

Ghost Orchid

A frog I have been called, but I have cell walls.

It is a flower and flowers have cell walls.

Threatened am I, but loved am I;

they are very rare.

Alone I hang, no one can find me.

They sort of hang on trees, according to Wikipedia.

A friend have I, the forgotten butterfly.

Only the giant sphinx moth is able to pollinate ghost orchids due to it's long proboscis(found by google search)

No one can replicate me, for I am unique:

Very rare.

Free I must be, for I perish in captivity.

It may not survive relocation or captivity.

I will dance for you, for only a week;

The bloom time.

If the world does not improve, my future is bleak.

Rare and maybe endangered.

To differentiate me from others I'll say the biggest hint of all: I am of the color gray.

That it is.

My spooky physique,

Ghost Orchid.

the witch, the toad; "The rarest ingredient of all" she would have crowed.

Rare?