The Homer Laughlin China Co. was an American china manufacturer. They produced so many items that they named the shapes instead of giving each pattern a name. It is not uncommon to find different shapes with the same pattern or decal.
The Angelus is the name of the shape of your Homer Laughlin platter. This particular shape is shown in the 1905 & 1906 catalogs from Sears and Montgomery Ward. It was in production until the late teens or early 1920's.
The Homer Laughlin Angelus shape is characterized by the scalloped rim and the tiny beads that are around the upper edge. The pattern is usually flowers of some type but it is not unusual to find other decals on it.
The Homer Laughlin Co. was founded in East Liverpool, Ohio in 1871 by brothers Homer and Shakespeare Laughlin. It is still in production today mainly remaking their popular Fiesta pattern and go with pieces. You can read the entire history here - http://www.fiestafactorydirect.com/t-about.aspx