CannTrust Holdings (NASDAQOTH: CNTTF) and Organigram Holdings (NASDAQOTH: OGRMF) have quite a bit in common. They have the same last name. They're both Canadian marijuana growers. And they both have similar opportunities in front of them.The two companies aren't exactly alike, though. Investors have been more optimistic about Organigram recently than they have been for CannTrust.