Davies, 23, who is closing in on a degree in bio-chemistry from UC Santa Cruz, inspects the weed Canna Care purchases from its patient growers.
He scans each plant variety - be it a "purple urkle" indica, a "cotton candy" sativa or a "golden kush" hybrid. He puts buds under his microscope and views a blown-up image on a computer screen, looking for signs of mold or fungus.
He seals the inspection with a smell test. He is well-trained for the scent of spoiled weed.
"Cannabis is something that will go bad over time," Davies says. When it does, he turns the grower - and their pot - away. "I sit them down and say, 'I sorry. But I believe you have powdery mildew,'" he says.
Davies' father, Bryan Davies, founded the Canna Care collective, which now has more than 5,000 patient members, five years ago. A devout Christian, he stocks its Del Paso Heights dispensary with Bibles and volumes on medicinal benefits of cannabis. Canna Care also hosts meetings for "Crusaders for Patients Rights," an advocacy group for access to medical pot.
Don Davies works behind a glass counter in a white lab coat, a signature for the dispensary's bud tenders.
He isn't sure how long he'll stay with the family enterprise. He wants to go to medical school.
"I hope he goes into cannabinoids research," says Canna Care director Lanette Davies, Don's mother, referring to properties in marijuana.
Davies said he prefers to become a general medicine physician - not a pot doc, particularly.
"I get bored easily," he says. "I have to switch to something new."
Pictured: Behind his ubiquitous microscope, Davies works the Canna Care counter. Paul Kitagaki Jr./firstname.lastname@example.org