
The anthemion logo as adopted by the Friends of the Alameda Free Library was taken from the architectural elements on either side of the entry of the old Carnegie Library Building at the corner of Oak and Santa Clara (see the photo to the right). The design is known architecturally as an anthemion (an-THEE-mee-on; plural anthemia), which is the Greek word for flower.
The anthemion is an ancient Greek design consisting of a number of radiating petals sometimes referred to as the honeysuckle or lotus palmette. The Greek anthemion is a version of a very widespread ancient decorative design derived from earlier Egyptian, Assyrian, and Aegean versions.

The anthemion was used widely by the Greeks to embellish ceramics as shown in the illustration. Later, it was used by both the Greeks and Romans to decorate a wide variety of objects as well as the roof lines and collumns of buildings.
For more information, check out the entry in the online Wikipedia.
The anthemion motif was a popular architectural element during the latter part of the 19th and early part of the 20th centuries. The design was used singly on antefixes—the ornamental blocks concealing tile-ends at the edges of a roof—or as a running ornament on friezes.
You can see examples of anthemia also decorating the roof-line of the building to the west of the old Alameda High School (see photo below).