Why does the sender of a submission show the wordpress multisite network instead of the subdomain?

I have a client that has a form on his domain. The domain is actually a subdomain of a larger Wordpress Network. When someone submits a form the email sent with the form information shows up with the sender being the "Wordpress Network" and not the subdomain. Is there any way to change that? The domain is mapped properly and functioning, so what needs to change to make it look like the emailed form came from that domain?