8-A12B

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-A

FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
PURSUANT TO SECTION 12(b) OR 12(g) OF THE
SECURITIES EXCHANGE ACT OF 1934

Senior Housing Properties Trust

Maryland
(State of organization) 04-3445278
(I.R.S. employer identification number)

400 Centre Street, Newton, Massachusetts
02458

If this form relates to the registration of a class of securities pursuant to Section 12(b) of the Exchange Act and is effective pursuant to General Instruction A.(c), check the following box: [X]

If this form relates to the registration of a class of securities pursuant to Section 12(g) of the Exchange Act and is effective pursuant to General Instruction A.(d), check the following box: [ ]

Securities to be registered pursuant to Section 12(b) of the Act:

Title of Each Class
to be so RegisteredJunior Participating Preferred Share Rights Name of Each Exchange on Which
Each Class is to be RegisteredNew York Stock Exchange

Securities to be registered pursuant to Section 12(g) of the Act:

None
(Title of Class)

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Item 1. Description of Registrant's Securities to be Registered.

        On March 10, 2004, the Board of Trustees of Senior Housing Properties Trust (the “Company”) declared a dividend distribution of one right for each of the Company’s outstanding common shares of beneficial interest, par value $.01 per share (the “Common Shares”), to holders of record of the Common Shares at the close of business on April 10, 2004. Each Right entitles the registered holder to purchase from the Company one one-thousandth of a preferred share of beneficial interest, par value $.01 per share, of the Company (the “Preferred Shares”) or in certain circumstances, to receive cash, property, Common Shares or other securities of the Company, at a purchase price of $35 per one one-thousandth of a Preferred Share (the "Purchase Price"), subject to adjustment (the “Rights”). The description and terms of the Rights are set forth in a Rights Agreement (the “Rights Agreement”) between the Company and EquiServe Trust Company, N.A., as Rights Agent.

        Initially, the Rights will be attached to all certificates representing the Common Shares and no separate Rights Certificates will be distributed. Subject to certain exceptions specified in the Rights Agreement, the Rights will separate from the Common Shares and a Distribution Date will occur upon the earlier of (i) 10 business days (or such later date as the Company’s Board of Trustees may determine before a Distribution Date occurs) following a public announcement by the Company that a person or group of affiliated or associated persons (an “Acquiring Person”) has acquired beneficial ownership of 10% or more of the outstanding Common Shares (the date of such announcement being the “Stock Acquisition Date”) or (ii) 10 business days (or such later date as the Company’s Board of Trustees may determine before a Distribution Date occurs) following the commencement of a tender offer or exchange offer that, if consummated, would result in a person becoming an Acquiring Person.

        Until the Distribution Date, (i) the Rights will be evidenced by the certificates for Common Shares and will be transferred with and only with such Common Share certificates, (ii) new Common Share certificates will contain a notation incorporating the Rights Agreement by reference, and (iii) the surrender for transfer of any certificates for Common Shares outstanding will also constitute the transfer of the Rights associated with the Common Shares represented by such certificates.

        The Rights are not exercisable until after the Distribution Date and will expire at the close of business on April 10, 2014, unless such date is extended or the Rights are earlier redeemed or exchanged by the Company as described below.

        As soon as practicable after the Distribution Date, Rights Certificates will be mailed to holders of record of the Common Shares as of the close of business on the Distribution Date and, from and after the Distribution Date, the separate Rights Certificates alone will represent the Rights. Except for Common Shares issued pursuant to exercises of stock options or as awards under an employee plan or arrangement granted or awarded as of the Distribution Date or upon the exercise, conversion or exchange of securities issued by the Company after the date of the Rights Agreement, or as otherwise determined by the Board of Trustees, Rights will only be issued with respect to Common Shares that were issued prior to the Distribution Date.

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        In the event (a “Flip-In Event”) a Person becomes an Acquiring Person (except pursuant to a tender or exchange offer for all outstanding Common Shares at a price and on terms which a majority of the Company’s Outside Trustees (as defined in the Rights Agreement) determines to be fair and not inadequate and to otherwise be in the best interests of the Company and its shareholders (a “Qualified Offer”)), each holder of a Right will thereafter have the right to receive, upon exercise of such Right, Common Shares (or, in certain circumstances, cash, property or other securities of the Company) having a Current Market Price (as defined in the Rights Agreement) equal to two times the exercise price of the Right. Notwithstanding the foregoing, following the occurrence of any Flip-In Event, all Rights that are, or (under certain circumstances specified in the Rights Agreement) were, beneficially owned by any Acquiring Person (or by certain related parties) will be null and void in the circumstances set forth in the Rights Agreement. However, Rights will not be exercisable following the occurrence of any Flip-In Event until such time as the Rights are no longer redeemable by the Company as set forth below.

        For example, at an exercise price of $35 per Right, each Right not owned by an Acquiring Person (or by certain related parties) following a Flip-In Event would entitle its holder to purchase $70 worth of Common Shares (or other consideration, as noted above) for $35. Assuming that the Current Market Value (as defined in the Rights Agreement) per Common Shares is $17.50 at such time, the holder of each valid Right would be entitled to purchase four Common Shares for $35.

        In the event (a “Flip-Over Event”) that, at any time on or after the Stock Acquisition Date, (i) the Company shall take part in a merger or other business combination transaction and the Company shall not be the surviving entity (other than with an entity which acquired the shares pursuant to a Qualified Offer) or (ii) the Company shall take part in a merger or other business combination transaction in which the Company is the surviving entity and the Common Shares are changed or exchanged (other than with an entity which acquired the shares pursuant to a Qualified Offer) or (iii) 50% or more of the Company’s assets, cash flow or earning power is sold or transferred, each holder of a Right (except Rights which previously have been voided, as set forth above) shall thereafter have the right to receive, upon exercise, a number of shares of common stock of the acquiring company having a Current Market Price equal to two times the exercise price of the Right.

        At any time after a person becomes an Acquiring Person and prior to the acquisition by such person or group of 50% or more of the outstanding Common Shares, the Company’s Board of Trustees may exchange the Rights (other than Rights owned by such person or group which have become void), in whole or in part, at an exchange ratio of one Common Share, or one one-thousandth of a Preferred Share (or of a share of a class or series of the Company’s preferred stock having equivalent rights, preferences and privileges), per Right (subject to adjustment).

        The Purchase Price payable and the number of Preferred Shares (or the amount of cash, property or other securities) issuable upon exercise of the Rights are subject to adjustment from time to time to prevent dilution (i) in the event of a stock dividend on, or a subdivision, combination or reclassification of, the Preferred Shares, (ii) if holders of the Preferred Shares are

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granted certain rights or warrants to subscribe for Preferred Shares or convertible securities at less than the Current Market Price of the Preferred Shares or (iii) upon the distribution to holders of the Preferred Shares of evidences of indebtedness or assets (excluding regular quarterly cash dividends) or of subscription rights or warrants (other than those referred to above). Pursuant to the Rights Agreement, the Company reserves the right to require prior to the occurrence of a Triggering Event (as defined in the Rights Agreement) that, upon exercise of Rights, a number of Rights be exercised so that only whole Preferred Shares will be issued.

        With certain exceptions, no adjustment in the Purchase Price payable upon exercise of the Rights will be required until cumulative adjustments amount to at least 1% of the Purchase Price. The Company is not required to issue fractional Preferred Shares upon the exercise of any Right. In lieu thereof, a cash payment may be made, as provided in the Rights Agreement.

        At any time until 10 business days following the Stock Acquisition Date, the Company may redeem the Rights in whole, but not in part, at a price of $.01 per Right (payable in cash, Common Shares or other consideration deemed appropriate by the Company’s Board of Trustees). In the event that a majority of the Board of Trustees is no longer comprised of Continuing Trustees (a “Section 23(a) Event”), then for the maximum period allowed under Maryland law following the first occurrence of a Section 23(a) Event, the rights cannot be redeemed unless there are Continuing Trustees and a majority of the Continuing Trustees concur with the Board of Trustees’ decision to redeem the rights. Immediately upon the action of the Company’s Board of Trustees ordering redemption of the Rights (with, where required, the concurrence of the Continuing Trustees), the Rights will terminate and the only right of the holders of Rights will be to receive the $.01 per Right redemption price. The term “Continuing Trustees” means any member of the Board of Trustees of the Company who was a member of the Board of Trustees prior to the date of the Rights Agreement, and any person who is subsequently elected to the Board of Trustees if such person is recommended or approved by a majority of the Continuing Trustees, but shall not include an Acquiring Person, or an affiliate or associate of an Acquiring Person, or any representative of the foregoing entities.

        Until a Right is exercised, the holder thereof, as such, will have no rights as a shareholder of the Company, including, without limitation, the right to vote or to receive dividends. While the distribution of the Rights should not be taxable to shareholders or to the Company, shareholders may, depending upon the circumstances, recognize taxable income in the event that the Rights become exercisable for Common Shares (or cash, property or other securities) of the Company or for common stock of the acquiring company or in the event of the redemption of the Rights as set forth above.

        Any provision of the Rights Agreement may be amended by the Board of Trustees of the Company prior to the Distribution Date. Thereafter, the provisions of the Rights Agreement may be amended by the Board of Trustees only in order to cure any ambiguity, defect or inconsistency, to make changes which do not adversely affect the interests of holders of Rights (excluding the interests of any Acquiring Person and certain other related parties) or to shorten or lengthen any time period under the Rights Agreement. For the maximum period allowed under Maryland law following the first occurrence of a Section 23(a) Event, the Rights Agreement can be amended only if there are Continuing Trustees and a majority of the Continuing Trustees

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concur with the amendment. Notwithstanding the foregoing, after such time as the Rights are not redeemable, the Rights Agreement may only be amended to cure any ambiguity, defect or inconsistency.

        Each Common Share outstanding at the close of business on the Record Date will receive one Right. So long as the Rights are attached to the Common Share, one additional Right (as such number may be adjusted pursuant to the provisions of the Rights Agreement) shall be deemed to be delivered for each Common Share issued or transferred by the Company in the future. Three hundred thousand Preferred Shares are initially reserved for issuance upon exercise of the Rights.

        The Rights may have certain anti-takeover effects. The Rights will cause substantial dilution to a person or group that attempts to acquire the Company in a manner which causes the Rights to become discount Rights unless the offer is conditional on a substantial number of Rights being acquired. The Rights, however, should not affect any prospective offeror willing to make an offer at a fair price and otherwise in the best interests of the Company and its shareholders as determined by the trustees or willing to negotiate with the Board. The Rights should not interfere with any merger or other business combination approved by the Board since the Board may, at its option, (i) at any time prior to the Distribution Date, amend the Rights Agreement, or (ii) at any time until 10 days following the Stock Acquisition Date redeem all, but not less than all, of the then outstanding Rights at the Redemption Price.

        The foregoing description of the Rights is qualified in its entirety by reference to the Rights Agreement, dated as of March 10, 2004, between the Company and EquiServe Trust Company, N.A., as Rights Agent, specifying the terms of the Rights, as well as the Company's Articles Supplementary, dated March 10, 2004 and filed with the Maryland Department of Assessments and Taxation on March 16, 2004.

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Item 2. Exhibits.

1. Composite Copy of Amended and Restated Declaration of Trust, dated September 20, 1999, as amended to date. (Incorporated by reference to the Company’s Current Report on Form 8-K dated January 21, 2004.)

2. Articles Supplementary dated May 11, 2000. (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2000.)

3. Articles Supplementary dated March 10, 2004. (Filed herewith.)

4. Composite Copy of Amended and Restated Bylaws, dated March 14, 2003, as amended to date. (Incorporated by reference to the Company’s Current Report on Form 8-K dated March 10, 2004.)

5. Rights Agreement, dated as of March 10, 2004, between the Company and EquiServe Trust Company, N.A., as Rights Agent, including all exhibits thereto. (Incorporated by reference to the Company’s Current Report on Form 8-K dated March 10, 2004.)

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SIGNATURE

        Pursuant to the requirements of Section 12 of the Securities Exchange Act of 1934, the registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: March 18, 2004 SENIOR HOUSING PROPERTIES TRUST


By: /s/ John R. Hoadley                 
      Name: John R. Hoadley
      Title: Treasurer and Chief Financial Officer

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EXHIBIT INDEX

Exhibit    Description

1. Composite Copy of Amended and Restated Declaration of Trust, dated September 20, 1999, as amended to date. (Incorporated by reference to the Company’s Current Report on Form 8-K dated January 21, 2004.)

2. Articles Supplementary dated May 11, 2000. (Incorporated by reference to the Company’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2000.)

3. Articles Supplementary dated March 10, 2004. (Filed herewith.)

4. Composite Copy of Amended and Restated Bylaws, dated March 14, 2003, as amended to date. (Incorporated by reference to the Company’s Current Report on Form 8-K dated March 10, 2004.)

5. Rights Agreement, dated as of March 10, 2004, between the Company and EquiServe Trust Company, N.A., as Rights Agent, including all exhibits thereto. (Incorporated by reference to the Company’s Current Report on Form 8-K dated March 10, 2004.)

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EX-2

EXHIBIT 2

SENIOR HOUSING PROPERTIES TRUST

ARTICLES SUPPLEMENTARY

        SENIOR HOUSING PROPERTIES TRUST, a Maryland real estate investment trust, having its principal office in Baltimore City, Maryland (hereinafter called the “Trust”), hereby certifies to the State Department of Assessments and Taxation of Maryland that:

        FIRST: Pursuant to authority expressly vested in the Board of Trustees by Article VI, Section 6.1 of the Amended and Restated Declaration of Trust of the Trust, dated September 20, 1999 as amended, (the “Declaration”), the Board of Trustees has duly reclassified 300,000 unissued Common Shares, of the Trust (from among the 80,000,000 Common Shares, $.01 par value, of the Trust which are authorized) into 300,000 Junior Participating Preferred Shares, par value $.01 per share, of the Trust.

        SECOND: The terms (including the designations and any preferences, conversion and other rights, voting powers, restrictions, limitations as to dividends, qualifications, and terms and conditions of redemption) of the Junior Participating Preferred Shares, par value $.01 per share, are as follows:

1.        Designation and Amount. The shares of such series shall be designated as “Junior Participating Preferred Shares” and the number of shares constituting such series shall be 1,000,000.

2.        Dividends and Distributions.

        (a)        Subject to the prior and superior rights of the holders of any shares of any series of Preferred Shares ranking prior and superior to the Junior Participating Preferred Shares with respect to dividends (if any), the holders of Junior Participating Preferred Shares shall be entitled to receive, when, as and if declared by the Board out of funds legally available for the purpose, quarterly dividends payable in cash on the 15th day of March, June, September and December in each year (each such date being referred to herein as a “Quarterly Dividend Payment Date”), commencing on the first Quarterly Dividend Payment Date after the first issuance of a Junior Participating Preferred Share or fraction thereof, in an amount per share (rounded to the nearest cent) equal to the greater of (X) $5 or (Y) subject to the provision for adjustment hereinafter set forth, 1,000 times the aggregate per share amount of all cash dividends, plus 1,000 times the aggregate per share amount (payable in kind) of all non-cash dividends or other distributions, other than a dividend payable in common shares of beneficial interest, par value $.01 per share, of the Trust (the “Common Shares”) or a subdivision of the outstanding Common Shares (by reclassification or otherwise), declared on the Common Shares, since the immediately preceding Quarterly Dividend Payment Date, or, with respect to the first Quarterly Dividend Payment Date, since the first issuance of any Junior Participating Preferred Share or fraction thereof. In the event the Trust shall at any time after March 10, 2004 (the “Rights Declaration Date”) (i) declare any dividend on Common Shares payable in Common Shares, (ii) subdivide the outstanding Common Shares or (iii) combine the outstanding Common Shares into a smaller number of

shares, then in each such case the amount to which holders of shares of Junior Participating Preferred Shares were entitled immediately prior to such event under clause (Y) of the preceding sentence shall be adjusted by multiplying such amount by a fraction, the numerator of which is the number of Common Shares outstanding immediately after such event and the denominator of which is the number of Common Shares that were outstanding immediately prior to such event.

        (b)        The Board shall declare a dividend or distribution on the Junior Participating Preferred Shares as provided in paragraph (a) above immediately after it declares a dividend or distribution on the Common Shares (other than a dividend payable in Common Shares); provided that, in the event no dividend or distribution shall have been declared on the Common Shares during the period between any Quarterly Dividend Payment Date and the next subsequent Quarterly Dividend Payment Date, a dividend of $5 per share on the Junior Participating Preferred Shares shall nevertheless be payable on such subsequent Quarterly Dividend Payment Date.

        (c)        Dividends shall begin to accrue and be cumulative on outstanding Junior Participating Preferred Shares from the Quarterly Dividend Payment Date next preceding the date of issue of such Junior Participating Preferred Shares unless the date of issue of such shares is prior to the record date for the first Quarterly Dividend Payment Date, in which case dividends on such shares shall begin to accrue from the date of issue of such shares, or unless the date of issue is a Quarterly Dividend Payment Date or is a date after the record date for the determination of holders of Junior Participating Preferred Shares entitled to receive a quarterly dividend and before such Quarterly Dividend Payment Date, in either of which events such dividends shall begin to accrue and be cumulative from such Quarterly Dividend Payment Date. Accrued but unpaid dividends shall not bear interest. Dividends paid on the Junior Participating Preferred Shares in an amount less than the total amount of such dividends at the time accrued and payable on such shares shall be allocated pro rata on a share-by-share basis among all such shares at the time outstanding. The Board may fix a record date for the determination of holders of Junior Participating Preferred Shares entitled to receive payment of a dividend or distribution declared thereon, which record date shall be not less than 10 and not more than 60 days prior to the date fixed for the payment thereof.

3.     Voting Rights. The holders of Junior Participating Preferred Shares shall have the following voting rights:

        (a)        Subject to the provision for adjustment hereinafter set forth, each Junior Participating Preferred Share shall entitle the holder thereof to 1,000 votes on all matters submitted to a vote of the shareholders of the Trust. In the event that the Board shall at any time after the Rights Declaration Date (i) declare any dividend on Common Shares payable in Common Shares, (ii) subdivide the outstanding Common Shares or (iii) combine the outstanding Common Shares into a smaller number of shares, then in each such case the number of votes per share to which holders of Junior Participating Preferred Shares were entitled immediately prior to such event shall be adjusted by multiplying such number by a fraction the numerator of which is the number of Common Shares outstanding immediately after such event and the denominator of which is the number of Common Shares that were outstanding immediately prior to such event.

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        (b)      Except as otherwise provided herein or by law, the holders of Junior Participating Preferred Shares and the holders of Common Shares shall vote together as one class on all matters submitted to a vote of shareholders of the Trust.

        (c)   (i)  If at any time dividends on any Junior Participating Preferred Shares shall be in arrears in an amount equal to six (6) quarterly dividends thereon, the occurrence of such contingency shall mark the beginning of a period (a “Default Period”) which shall extend until such time when all accrued and unpaid dividends for all previous quarterly dividend periods and for the current quarterly dividend period on all Junior Participating Preferred Shares then outstanding shall have been declared and paid or set apart for payment. During each Default Period, all holders of Preferred Shares (including holders of the Junior Participating Preferred Shares) with dividends in arrears in an amount equal to six (6) quarterly dividends thereon, voting as a class, irrespective of series, shall have the right to elect two (2) Trustees.

                (ii)  During any Default Period, such voting right of the holders of Junior Participating Preferred Shares may be exercised initially at a special meeting called pursuant to subparagraph (iii) of this Section 3(c) or at an annual meeting of shareholders, and thereafter at annual meetings of shareholders, provided that neither such voting right nor the right of the holders of any other series of Preferred Shares, if any, to increase, in certain cases, the authorized number of Trustees shall be exercised unless the holders of ten percent (10%) in number of Preferred Shares outstanding shall be present in person or by proxy. The absence of a quorum of the holders of Common Shares shall not affect the exercise by the holders of Preferred Shares of such voting right. At any meeting at which the holders of Preferred Shares shall exercise such voting right initially during an existing Default Period, they shall have the right, voting as a class, to elect Trustees to fill up to two (2) vacancies, if any, in the Board or, if such right is exercised at an annual meeting, to elect two (2) Trustees. The holders of Preferred Shares shall have the right to make such increase in the number of Trustees as shall be necessary to permit the election by them at any special meeting of two (2) Trustees. After the holders of Preferred Shares shall have exercised their right to elect Trustees in any Default Period and during the continuance of such period, the number of Trustees shall not be increased or decreased except by vote of the holders of Preferred Shares as herein provided or pursuant to the rights of any equity securities ranking senior to or pari passu with the Junior Participating Preferred Shares, if any.

                (iii)  Unless the holders of Preferred Shares shall, during an existing Default Period, have previously exercised their right to elect Trustees, the Board may order, or any shareholder or shareholders owning in the aggregate not less than ten percent (10%) of the total number of Preferred Shares outstanding, irrespective of series, may request, the calling of a special meeting of the holders of Preferred Shares, which meeting shall thereupon be called by the Board or the President, any Vice President or the Secretary of the Trust. The Secretary of the Trust shall give notice of such meeting and of any annual meeting at which holders of Preferred Shares are entitled to vote pursuant to this paragraph (c)(iii) to each holder of record of Preferred Shares by mailing a copy of such notice to him at his last address as the same appears on the books of the Trust. Such meeting shall be called for a time not earlier than fifteen (15) days and not later than sixty (60) days after such order or request. If such meeting is not called within sixty (60) days after such order or request, such meeting may be called on similar notice by any

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shareholder or shareholders owning in the aggregate not less than ten percent (10%) of the total number of Preferred Shares outstanding. Notwithstanding the provisions of this paragraph (c)(iii), no such special meeting shall be called during the period within sixty (60) days immediately preceding the date fixed for the next annual meeting of the shareholders.

                (iv)  In any Default Period, the holders of Common Shares, and (if applicable) other classes of shares of beneficial interest of the Trust (all Trust shares being referred to as “Shares”), shall continue to be entitled to elect the whole number of Trustees until the holders of Preferred Shares shall have exercised their rights to elect two (2) Trustees voting as a class, after the exercise of which right, (X) the Trustees so elected by the holders of Preferred Shares shall continue in office until their successors shall have been elected by such holders or until the expiration of the Default Period, and (Y) any vacancy in the Board shall (except as provided in paragraph (c)(ii) of this Section 3) be filled by vote of a majority of the remaining Trustees theretofore elected by the holders of the class or classes of Shares which elected the Trustee whose office shall have become vacant. References in this paragraph (c) to Trustees elected by the holders of a particular class of Shares shall include Trustees elected by such Trustees to fill vacancies as provided in clause (Y) of the foregoing sentence.

                (v)  Immediately upon the expiration of a Default Period, (X) the right of the holders of Preferred Shares as a class to elect Trustees shall cease, (Y) the term of any Trustees elected by the holders of Preferred Shares as a class shall terminate, and (Z) the number of Trustees shall be such number as may be provided for in the Declaration, any Article Supplementary or the By-Laws of the Trust, irrespective of any increase made pursuant to the provisions of paragraph (c)(ii) of this Section 3 such number being subject, however, to change thereafter in any manner provided by law, or in the Declaration, any Article Supplementary or the By-Laws of the Trust). Any vacancies in the Board effected by the provisions of clauses (Y) and (Z) in the preceding sentence may be filled by a majority of the remaining Trustees.

        (d)        Except as set forth herein, holders of Junior Participating Preferred Shares shall have no special voting rights and their consent shall not be required (except to the extent they are entitled to vote with holders of Common Shares as set forth herein) for taking any trust action.

4.        Certain Restrictions.

        (a)        Whenever quarterly dividends or other dividends or distributions payable on the Junior Participating Preferred Shares as provided in Section 2 are in arrears, thereafter and until all accrued and unpaid dividends and distributions, whether or not declared, on Junior Participating Preferred Shares outstanding shall have been paid in full, the Trust shall not:

                (i)  declare or pay dividends on, make any other distributions on, or redeem or purchase or otherwise acquire for consideration any Shares ranking junior (either as to dividends or upon liquidation, dissolution or winding up) to the Junior Participating Preferred Shares;

                (ii)  declare or pay dividends on or make any other distributions on any Shares ranking on a parity (either as to dividends or upon liquidation, dissolution or winding up) with

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the Junior Participating Preferred Shares except dividends paid ratably on the Junior Participating Preferred Shares and all such parity Shares on which dividends are payable or in arrears in proportion to the total amounts to which the holders of all such Shares are then entitled;

                (iii)  redeem or purchase or otherwise acquire for consideration Shares ranking on a parity (either as to dividends or upon liquidation, dissolution or winding up) with the Junior Participating Preferred Shares provided that the Trust may at any time redeem, purchase or otherwise acquire any such parity Shares in exchange for any Shares ranking junior (either as to dividends or upon dissolution, liquidation or winding up) to the Junior Participating Preferred Shares;

                (iv)  purchase or otherwise acquire for consideration any Junior Participating Preferred Shares, or any Shares ranking on a parity with the Junior Participating Preferred Shares, except pursuant to Section 4(a)(iii) or in accordance with a purchase offer made in writing or by publication (as determined by the Board) to all holders of such shares upon such terms as the Board, after consideration of the respective annual dividend rates and other relative rights and preferences of the respective series and classes, shall determine in good faith will result in fair and equitable treatment among the respective series or classes.

        (b)        The Trust shall not permit any subsidiary of the Trust to purchase or otherwise acquire for consideration any Shares of the Trust unless the Trust could, under paragraph (a) of this Section 4, purchase or otherwise acquire such shares at such time and in such manner.

5.        Reacquired Shares. Any Junior Participating Preferred Shares, purchased or otherwise acquired by the Trust in any manner whatsoever shall be retired and cancelled promptly after the acquisition thereof. All such shares shall upon their cancellation become authorized but unissued Preferred Shares and may be reissued as part of a new series of Preferred Shares to be created by resolution or resolutions of the Board, subject to the conditions and restrictions on issuance set forth herein.

6.        Liquidation, Dissolution or Winding Up.

        (a)        Upon any liquidation (voluntary or otherwise), dissolution or winding up of the Trust, no distribution shall be made to the holders of Shares ranking junior (either as to dividends or upon liquidation, dissolution or winding up) to the Junior Participating Preferred Shares, unless, prior thereto, the holders of Junior Participating Preferred Shares shall have received $1,000.00 per share, plus an amount equal to accrued and unpaid dividends and distributions thereon, whether or not declared, to the date of such payment (the “Liquidation Preference”). Following the payment of the full amount of the Liquidation Preference, no additional distributions shall be made to the holders of Junior Participating Preferred Shares, unless, prior thereto, the holders of Common Shares shall have received an amount per share (the “Common Adjustment”) equal to the quotient obtained by dividing (i) the Liquidation Preference by (ii) 1,000 (as appropriately adjusted as set forth in subparagraph (c) below to reflect such events as stock splits, stock dividends and recapitalization with respect to the Common Shares) (such number in clause (ii) immediately above being referred to as the “Adjustment Number”). Subject

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to the rights of any other series of Preferred Shares then outstanding, if any, following the payment of the full amount of the Liquidation Preference and the Common Adjustment in respect of all outstanding shares of Junior Participating Preferred Shares and Common Shares, respectively, holders of Junior Participating Preferred Shares and holders of shares of Common Shares shall receive their ratable and proportionate share of the remaining assets to be distributed in the ratio of the Adjustment Number to one (1) with respect to such Junior Participating Preferred Shares and Common Shares, on a per Share basis, respectively.

        (b)        In the event, however, that there are not sufficient assets available to permit payment in full of the Liquidation Preference and the liquidation preferences of all other series of Preferred Shares, if any, which rank on a parity with the Junior Participating Preferred Shares, then such remaining assets shall be distributed ratably to the holders of such parity Shares (including the Junior Participating Preferred Shares) in proportion to their respective liquidation preferences. In the event, however, that there are not sufficient assets available to permit payment in full of the Common Adjustment after satisfaction of the liquidation preferences of all series of Preferred Shares, if any, then such remaining assets shall be distributed ratably to the holders of Common Shares.

        (c)        In the event the Trust shall at any time after the Rights Declaration Date (i) declare any dividend on Common Shares payable in Common Shares, (ii) subdivide the outstanding Common Shares or (iii) combine the outstanding Common Shares into a smaller number of shares, then in each such case the Adjustment Number in effect immediately prior to such event shall be adjusted by multiplying such Adjustment Number by a fraction the numerator of which is the number of Common Shares outstanding immediately after such event and the denominator of which is the number of shares of Common Shares that were outstanding immediately prior to such event.

7.        Consolidation, Merger, etc. In case the Trust shall enter into any consolidation, merger, combination or other transaction in which the Common Shares are exchanged for or changed into other stock or securities, cash or any other property, then in any such case the Junior Participating Preferred Shares shall at the same time be similarly exchanged or changed in an amount per share (subject to the provision for adjustment hereinafter set forth) equal to 1,000 times the aggregate amount of shares, securities, cash or any other property (payable in kind), as the case may be, into which or for which each Common Share is changed or exchanged. In the event the Trust shall at any time after the Rights Declaration Date (i) declare any dividend on Common Shares payable in Common Shares, (ii) subdivide the outstanding Common Shares or (iii) combine the outstanding Common Shares into a smaller number of Shares, then in each such case the amount set forth in the preceding sentence with respect to the exchange or change of Junior Participating Preferred Shares shall be adjusted by multiplying such amount by a fraction the numerator of which is the number of Common Shares outstanding immediately after such event and the denominator of which is the number of Common Shares that were outstanding immediately prior to such event.

8.        Redemption. The Junior Participating Preferred Shares shall not be redeemable.

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9.        Ranking. The Junior Participating Preferred Shares shall rank junior to all other series of the Trust’s Preferred Shares as to the payment of dividends and the distribution of assets, unless the terms of any such series shall provide otherwise.

10.        Amendment. At such time as Junior Participating Preferred Shares are outstanding, neither the Declaration nor this Articles Supplementary shall be amended, nor shall an Article Supplementary of the Trust be filed or amended, in any manner which would materially alter or change the powers, preferences or special rights of the Junior Participating Preferred Shares so as to affect them adversely without the affirmative vote of the holders of a majority or more of the outstanding Junior Participating Preferred Shares voting separately as a class.

11.        Fractional Shares. Junior Participating Preferred Shares may be issued in fractions of a share which shall entitle the holder, in proportion to such holder’s fractional shares, to exercise voting rights, receive dividends, participate in distributions and have the benefit of all other rights of a holder of Junior Participating Preferred Shares.

[Remainder of Page Intentionally Left Blank]

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        IN WITNESS WHEREOF, SENIOR HOUSING PROPERTIES TRUST has caused these Articles Supplementary to be signed in its name and on its behalf by a majority of its entire Board of Trustees and witnessed by its Secretary on March 10, 2004.

WITNESS:


/s/ Camille Balletto SENIOR HOUSING PROPERTIES TRUST


By: /s/ David J. Hegarty
      David J. Hegarty
      President, Chief Operating Officer and Secretary

        THE UNDERSIGNED, ASSISTANT SECRETARY OF SENIOR HOUSING PROPERTIES TRUST, with respect to the foregoing Articles Supplementary of which this Certificate is made a part, hereby acknowledges in the name and on behalf of said Trust, the foregoing Articles Supplementary to be the act of said Trust and hereby certifies that the matters and facts set forth herein with respect to the authorization and approval thereof are true in all material respects under the penalties of perjury.

/s/ Jennifer B. Clark
Jennifer B. Clark
Assistant Secretary

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