The almost total absence from Homer not only of "Dorians " but of " Ionians " and even of " Hellenes "leads to the conclusion that the diagrammatic genealogy of the " sons of Hellen " is of post-Homeric date; and that it originated as an attempt to classify the Doric, Ionic and Aeolic groups of Hellenic settlements on the west coast of Asia Minor, for here alone do the three names correspond to territorial, linguistic and political divisions.
By photography and diagrammatic records the clinical work of hospital wards has been brought into some better definition, and teaching made more accurate and more impressive.
In the diagrammatic family tree of the Greek people, as it appears in the Hesiodic catalogue (6th century) and in Hellanicus (5th century), the " sons of Hellen " are Dorus, Xuthus (father of Ion and Achaeus) and Aeolus.
For diagrammatic purposes each member is sufficiently represented by a straight line terminating at the two joints; these lines will be referred to as the bars of the frame.
Diagrammatic longitudinal section of cone, showing the axis (ax) bearing the bracts (br) with peltate sporangiophores (sp) springing from their axils; sm, sporangia.