C.H.T Marshall Collage

Hello, I hoped someone might be able to help me with this piece. On the back, it reads "From Shanghai China" in pencil, but there's a sticker also, which is for an early 20th-century photographer.

I had thought maybe, the art was bought in China and the sticker was for the framer but there's nothing online to say that C.H.T Marshall has a framing business, but guess photography and framing go hand in hand. My main question is, what do you think the collage is made from? It's quite shiny material but I can't think what it might be...Thank you :)

It could be made of dyed wheat straw.

Thank you, I think you're right