i didnt actually look but couldnt imagine what else it could be. could go either way apparently. i guess my ass isn a proper noun though i think it deserves as much respect.

It’s when the car belongs to a person named Chris, or we’re talking about the petals of a crocus that the rules get blurry. Most experts and guides say you should add an apostrophe and an S to both proper and common nouns to make them possessive even when they end in S. So, using the examples above, it would be:

 Chris’s car

the crocus’s petals 

Not everyone agrees with this method, however, and some, such as the Associated Press Stylebook, nod in favor of adding only an apostrophe to make a proper noun possessive, such as:

Chris’ car

Dickens’ novels

To add even more confusion, AP Style also has an exception if the word following the possessive starts with an S, stating that in those cases only the apostrophe should be added. So it would be:

Texas’s people

Texas’ streams