Porn star Kendra Sunderland is learning the hard way ... marijuana is still illegal in Texas.
The adult-film actress got busted in Montgomery County, Texas for felony possession of a controlled substance ... in this instance, marijuana ... according to new legal docs obtained by TMZ.
Kendra's arrest went down in broad daylight -- a little past high noon on August 1, and prosecutors say she had less than one gram of THC. Cops aren't saying what led to her bust.
TMZ obtained Kendra's mug shot ... and she's looking pretty pouty.
Kendra tells TMZ ... "I've been advised not to say anything. I'm not trying to incriminate myself any further. I just know that I'm not a criminal. I'm just a stoner."
Kendra is 29 and she lives in Nevada, where adults 21 years and older can legally possess up to 2.5 ounces of cannabis in a private residence or a licensed social use lounge -- but things are still different down in the Lone Star State, where weed possession is still very illegal.
The docs show Kendra was released from custody after posting a $1,000 bond ... and she's due in the Conroe County courthouse next month.