Prospectus exerpt:  We are offering 10,000,000 shares of our 71/4% Series E cumulative redeemable preferred shares, which we refer to in this prospectus supplement as the Series E Preferred Shares. We will pay cumulative distributions on the Series E Preferred Shares in the amount of $1.8125 per share each year, which is the equivalent of 7.25% of the $25.00 liquidation preference per share. Distributions on the Series E Preferred Shares sold in this offering will be payable quarterly in arrears, on the 15th day of February, May, August and November of each year, beginning August 15, 2011.

Generally, we are not allowed to redeem the Series E Preferred Shares until May 15, 2016. On and after May 15, 2016, we may, at our option, redeem the Series E Preferred Shares, in whole or from time to time in part, for cash at a redemption price of $25.00 per share, plus any accrued and unpaid distributions to but excluding the date of redemption. In addition, upon the occurrence of a change of control the result of which our common shares of beneficial interest, par value $0.01 per share, or our common shares, and the common securities of the acquiring or surviving entity (or American Depositary Receipts, or ADRs, representing such securities) are not listed on the New York Stock Exchange, or the NYSE, the NYSE Amex Equities, or the NYSE Amex, or the NASDAQ Stock Market, or NASDAQ, or listed or quoted on a successor exchange or quotation system, we may, at our option, redeem the Series E Preferred Shares, in whole or in part and within 120 days after the first date on which such change of control occurred, by paying $25.00 per share, plus any accrued and unpaid distributions to but excluding the date of redemption. If we exercise any of our redemption rights relating to the Series E Preferred Shares, the holders of Series E Preferred Shares will not have the conversion right described below. The Series E Preferred Shares have no maturity date and will remain outstanding indefinitely unless redeemed by us or converted in connection with a change of control by the holders of Series E Preferred Shares.