Document type definition. A document type definition (DTD) is a set of markup declarations that define a document type for an SGML-family markup language (SGML, XML, HTML). A Document Type Definition (DTD) defines the legal building blocks of an XML document. It defines the document structure with a list of legal elements and attributes. A DTD can be declared inline inside an XML document, or as an external reference.
American hornbeam. The American hornbeam is a native forest understory tree in the Chicago area, making it useful for shady landscapes and naturalized or woodland gardens.New leaves emerge reddish-purple, changing to dark green, then turn yellow to orange-red in the fall, offering a kaleidoscope of color throughout the year.merican hornbeam. The American hornbeam is a native forest understory tree in the Chicago area, making it useful for shady landscapes and naturalized or woodland gardens.
American Hornbeam: Nicknamed beech because of the leaf similarity, this tree is actually in the birch family. Its name horn (tough) and beam (strong) describes the tree's hard wood. Silver Maple: Easily recognized in the summer by the silvery underside color, the leaves turn yellowish-orange in the fall. White Oak: A widespreading tree-both in its branches and range throughout the US. Sassafras: Look for this tree in all color ranges! Also, look for at least two different leaf shapes.