Prospectus excerpt:  We are selling 17,000,000 depositary shares (ôDepositary Sharesö) each representing 1/1,000 of a share of a 6.35% Cumulative Preferred Share of Beneficial Interest, Series R (ôPreferred Sharesö). The Preferred Shares represented by the Depositary Shares will be deposited with Computershare Trust Company, N. A., as depositary. As a holder of Depositary Shares, you will be entitled to all proportional rights, preferences and privileges of the Preferred Shares. We have granted the underwriters an option to purchase up to 2,550,000 additional Depositary Shares to cover over-allotments. The following is a summary of the Preferred Shares: We will pay cumulative distributions on the Preferred Shares, from the date of original issuance, at the rate of 6.35% of the liquidation preference per year ($1.5875 per year per Depositary Share). We will pay distributions on the Preferred Shares quarterly, beginning on September 30, 2011 (with the payment on that date being based pro rata on the number of days from the original issuance of the Preferred Shares). We are not allowed to redeem the Preferred Shares before July 26, 2016, except in order to preserve our status as a real estate investment trust. On and after July 26, 2016, we may, at our option, redeem the Preferred Shares by paying you $25.00 per Depositary Share, plus any accrued and unpaid distributions. The Preferred Shares have no stated maturity and are not subject to any sinking fund or mandatory redemption and are not convertible into any other securities.