Gary -
Here's an example from the Regulations on taxable fringe benefits that is also helpful in answering your question (and seems to be a more fuller explanation to the IRS's own publication I cited above). If the employee can demonstrate a business-use percentage for the membership, then that amount is a non-taxable fringe benefit. The amount allocable to personal-use, if reimbursed by the employer, will be taxable to the employee, though. Regardless of business-use by the employee, the club dues will be non-deductible to the employer as I mentioned.
Example 1. Assume that Company X provides Employee B with a country club membership for which it paid $20,000. B substantiates, within the meaning of paragraph (c) of this section, that the club was used 40 percent for business purposes. The business use of the club (40 percent) may be considered a working condition fringe benefit, notwithstanding that the employer's deduction for the dues allocable to the business use is disallowed by section 274(a)(3), if X does not treat the club membership as compensation under section 274(e)(2). Thus, B may exclude from gross income $8,000 (40 percent of the club dues, which reflects B's business use). X must report $12,000 as wages subject to withholding and payment of employment taxes (60 percent of the value of the club dues, which reflects B's personal use). B must include $12,000 in gross income. X may deduct as compensation the amount it paid for the club dues which reflects B's personal use provided the amount satisfies the other requirements for a salary or compensation deduction under section 162.
Treasury Regulation §1.132-5(s)(3).
http://www.taxalmanac.org/index.php/Treasury_Regulations,_Subchapter_A,_Sec._1.132-5