Lippincott had 2 basic bowl designs that they used for their stemware. One was called the Derby and it is characterized by more V-shaped bowl. The other shape is the Belfont/Belmont. The reprinted catalog pages in Great American Glass of the Roaring 20's & Depression Era, Book 2, have it spelled Belfont most of the time and Belmont only once. The Belfont seems to have more of a rounded shape at the bottom of its bowl.
Based on these observations, it is believed that the 2 outside stems in the picture are examples of the Belfont stem and the item in the middle is an example of the Derby stem. Obviously, there needs to be more study to determine this line of thinking.
All three pieces have Lippincott's Bird O' Paradise etch.