Buyer Beware: Cats Claw (Uncaria tomentosa Willd.)??   I purchased these two bark specimens from two different herb purveyors in Chicago's Mexico town (18th Street, west of Chinatown).  Turns out both specimens are NOT Cat's Claw.   One of the pharmacists said,  "It is too difficult to get it and there are many herbs called cat's claw..."
To be certain you have Cat's claw buy the standardized over-the-counter preparation.

BE INFORMED: It is well worth your time to research the company you buy your herbs from.   Make certain the herb is authentic and of superior quality.   Find a knowledgeable and informed dealer.  And make certain they take time to answer all your questions so you can leave the store confident you got what you paid for.  (More)