The Mycologist has been very decidedly not turning his head in the Soft-Hearted Maven's direction. Only when she approaches, he greets her with a sweet smile. He listens politely.

"Purchase? My dear colleague," on the academic grounds, all are colleagues, "art thou implying that this experimental mixture that has not been approved by the Ministry of Health and Sanitation is sold somewhere? That taxes due for such commerce are paid to Mr Spices and slash or Mr Apples?"
He waits for a beat and then drops the theatrical hand back down to the table: "This is merely a batch that is a by-product of experimental breeding of fungi. It's existence has academical reasons. There is not even a patent yet. As such, no, thou art not able to purchase any amount of packs of finely ground fungal powder. However, if thou art willing to participate in gustatory research regarding the powder's properties, accompany me to my laboratory once this class is over, and thou wilt be provided with a sample."

He probably could have just said: "I'll give you one for free," but where would the fun be in that?