On April 1, the U.S. Patent and Trademark Office created a new trademark category: “Processed plant matter for medicinal purposes, namely medical marijuana.” The patent office, part of the Department of Commerce, posted the new category on its website.

The change set off a land rush by pot dealers in the 14 states where laws permit medical-marijuana sales.

Keef Cola

The patent office received more than 250 pot-related trademark applications in the three months after it created the new trademark category. There were applications for trademarks on “Tartukan Death Weed,” “Pot-N-Candy,” “Namers Nirvana” and numerous businesses incorporating “Green” and “4:20″—a number that pot smokers often associate with weed, sometimes smoking it at 4:20 p.m. and celebrating April 20 as a pro-pot holiday. Two companies applied to trademark psychoactive sodas named Keef Cola and Canna Cola.

The trademark rush began to haze the mellow of pot traders.  Some staked claims on rights to long-used names such as like Maui Wowie, Chronic,  Purple Haze and Acapulco Gold, made famous by comedian Tommy Chong more than 30 years ago. Arguments flared over whether such  long-used pot names are subject to “prior art,” meaning their use in the past precludes a trademark.

Weed entrepreneurs hired mainstream intellectual-property law firms like Knobbe Martens in Southern California and Weide & Miller (that’s right) in Las Vegas to register their weed trade names.

But last week the patent office snuffed out the promise of federal recognition. After questions about the new pot-trademark category from a Wall Street Journal reporter, a patent-office spokesman said the office planned to remove the new pot classification by week’s end, and the category is now off the website.

Marijuana dealers, their appetites whetted by the three months of hope, said they haven’t given up. Scott Ridell, a brand-development consultant for Panatella Brands, a Colorado pot-grower consortium, said his clients are still “moving forward” with branding efforts and hope the patent office will grant trademarks.

Keep smoking the weed dude, you’re in for a long wait.