Difference between Lucene and Zend Search Lucene

Please is anyone know the difference between Zend Search Lucene and Lucene? Thanks in advance.

From the manual:

Zend_Search_Lucene is a general purpose text search engine written entirely in PHP 5. Since it stores its index on the filesystem and does not require a database server, it can add search capabilities to almost any PHP-driven website. Zend_Search_Lucene supports the following features:

• Ranked searching - best results returned first
• Many powerful query types: phrase queries, boolean queries, wildcard queries, proximity queries, range queries and many others.
• Search by specific field (e.g., title, author, contents)

Zend_Search_Lucene was derived from the Apache Lucene project. The currently (starting from ZF 1.6) supported Lucene index format versions are 1.4 - 2.3. For more information on Lucene, visit http://lucene.apache.org/java/docs/.