Drug info - Pitchuri ?

[Benga]

hello all

would anyone have info on what is commonly described as the "mild narcotic" (whatever that means, since the term is often used incorrectly, especially in North America) used by Australian aboriginal tribes ? it was dipped in ashes ( an alkali, not unlike coca or betel), and chewed in quids.
i couldn't find any sources identifying this plant clearly, but i'm sure they exist. It might be tobacco related, and i also found some references to Nicotiania suaveolens, porcupine grass and Portulaea filifolia.

thanks

b