Green’s Dictionary of Slang

(drugs) marijuana; a marijuana cigarette.

1916		F. Elmer A Mexican Diary [typescript] 281: The uninitiated were warned against the wiles and seductions of a much-to-be-dreaded Mexican personage rejoicing in the name of ‘Mary Anna!’.
1939		C.R. Cooper Designs in Scarlet 147: ‘Boojies’ or ‘Mary Anns,’ as marijuana cigarettes are known.
1940		‘Jargon of Marihuana Addicts’ in AS XV:3 Oct. 336/2: The cigarettes are usually called reefers, but other names are: [...] Mary Anns, Mary Janes.
1953		Anslinger & Tompkins Traffic In Narcotics 312: Mary Ann. A marihuana cigarette.
1969		R.R. Lingeman Drugs from A to Z (1970).
1971		‘Hassan-i-Sabbah’ Leaves of Grass 1: Weed / Mary Ann / Gauge.
1980		E. Folb Runnin’ Down Some Lines 171: Vernacular expressions reflect a corruption, abbreviation, or play on the word itself (maryanne, maryjane, mariwegee).
2001		ONDCP Street Terms 14: Mary Ann — Marijuana.