How many different lexemes, word-forms and orthographical words are there in the following sentence? At the second drum roll, they have to roll out the flag and have it up the mast in fifteen seconds.

In linguistics, the term is lexeme represents the basic or dictionary form of the word. Lexemes are abstract representations, which presumably are listed in the brain in a component called the lexicon. Each inflected form of a lexeme is called a word-form.

Explanation:

http://www.sfu.ca/person/dearmond/323/323%20/323%20Morphology%202.ppt

the answer is:

magna carta

  this riddles' answer is library.

  the "leaves" are a reference to the books' pages that the library contains; the branches are a network of libraries that connect multiple libraries' collections, resources, and items in a system of a common database, integrating them; the branches' organization are a useful management tool for coordinating the multiple collections many libraries have.