Hackberry

Can anyone please help me with an ingredient I need to purchase for a recipe? I have a Japanese guest staying with me who wishes to cook a meal called 'Chicken Cake Nabe's'. One of the ingredients required is a packet of Hackberries. As I live in Australia I don't think I can purchase them here. Do you know of something eles similar I could use??
Thankyou.

for nabe dishes in general, as alternatives, you can use vegetables including chinese mushrooms, carrots, chinese cabbage or cabbage, leeks or spring onions, tofu and potatoes.

I'm starting to wonder if the ingredient she/he is looking for is a kind of mushroom called "enoki" - skinny white mushrooms. The reason behind my suspicion is that (for one thing, if it's "nabe" - hoto pot dish, a lot of vegetables including mushrooms are used, and) the word "enoki," if you look it up in dictionaries, does lead you to the word "hackberry," though this name hackberry refers to a family of trees, not the mushrooms which happen to have the same word "enoki" as part of its name, but not the same.