Section 9--310. When  Filing  Required  to  Perfect Security Interest or
                    Agricultural Lien; Security Interests and Agricultural
                    Liens to Which Filing Provisions Do Not Apply.
    (a) General rule: perfection by filing. Except as  otherwise  provided
  in  subsection  (b) and Section 9--312(b), a financing statement must be
  filed to perfect all security interests and agricultural liens.
    (b) Exceptions: filing not necessary. Except as provided in subsection
  (d), the filing of a financing statement is not necessary to  perfect  a
  security interest:
         (1) that is perfected under Section 9--308(d), (e), (f), or (g);
         (2) that is perfected under Section 9--309 when it attaches;
         (3) in  property  subject  to  a  statute,  regulation, or treaty
             described in Section 9--311(a);
         (4) in goods in possession of a bailee which is  perfected  under
             Section 9--312(d)(1) or (2);
         (5) in  certificated securities, documents, goods, or instruments
             which is perfected without filing or possession under Section
             9--312(e), (f), or (g);
         (6) in collateral in the secured party's possession under Section
             9--313;
         (7) in a certificated security which is perfected by delivery  of
             the  security  certificate to the secured party under Section
             9--313;
         (8) in deposit accounts,  electronic  chattel  paper,  investment
             property,  or  letter-of-credit  rights which is perfected by
             control under Section 9--314;
         (9) in proceeds which is perfected under Section 9--315;
         (10) that is perfected under Section 9--316; or
         (11) that is a cooperative organization security interest.
    (c) Assignment of perfected security  interest.  If  a  secured  party
  assigns  a  perfected  security  interest or agricultural lien, a filing
  under this article is not required to continue the perfected  status  of
  the  security  interest  against  creditors  of and transferees from the
  original debtor.
    (d) Special rule for cooperative interests. Except for  a  cooperative
  organization  security  interest,  a  security interest in a cooperative
  interest may be perfected only by filing a financing statement.