What is "theae folium"?

I wanted to buy black tea at a pharmacy and the pharmacist told me that russian tea is actually black tea so I bought it instead.It's made out of theae folium leaves and for some reason I can't find anything about that plant on the internet and I know that black tea is made out of camelia sinensis leaves, not theae folium.Can anyone tell me what is this plant and is it really russian tea (i found somewhere that russian tea is made from a different plant) and what is this "Russian" tea good for?