(a) A tax, as follows, is levied on and payable by any merchant of unauthorized substances:

(1) Forty cents (40¢) for each gram, or fraction thereof, of harvested marijuana stems and stalks that have been separated from and are not mixed with any other parts of the marijuana plant;

(2) Three dollars and fifty cents ($3.50) for each gram, or fraction thereof, of marijuana, other than separated stems and stalks taxed under subdivision (a)(1) or plants with foliation taxed under subdivision (a)(3);

(3) Three hundred fifty dollars ($350) per plant, whether growing or detached from the soil, on each marijuana plant with foliation;

(4) Fifty dollars ($50.00) for each gram, or fraction thereof, of cocaine;

(5) Two hundred dollars ($200) for each gram, or fraction thereof, of any other controlled substance, controlled substance analogue or low-street-value drug that is sold by weight;

(6) Fifty dollars ($50.00) for each ten (10) dosage units, or fraction thereof, of any low-street-value drug that is not sold by weight;

(7) Two hundred dollars ($200) for each ten (10) dosage units, or fraction thereof, of any other controlled substance or controlled substance analogue that is not sold by weight;

(8) Thirty-one dollars and seventy cents ($31.70) for each gallon, or fraction thereof, of illicit alcoholic beverages sold by the drink; or

(9) Twelve dollars and eighty cents ($12.80) for each gallon, or fraction thereof, of illicit alcoholic beverages not sold by the drink.

(b) A quantity of marijuana or other unauthorized substance is measured by the weight of the substance whether pure, impure or dilute, or by the number of dosage units in the merchant's possession when the substance is not sold by weight. A quantity of an unauthorized substance is dilute if it consists of a detectable quantity of pure controlled substance and any excipients or fillers.

(c) For purposes of this part, a person constructively possesses an unauthorized substance when the person has:

(1) Knowledge of the unauthorized substance; and

(2) The ability and intention to exercise control over the unauthorized substance.