This is a relatively easy one, because there are only six photos, one of each type:

Regelia (R), Regelia Hybrid (RH), Regeliocyclus (RC), Oncocyclus (O), Oncocylus Hybrid (OH), and Oncogelia (OG). Without consulting any Checklists, my List of Cultivars, or my Photo Gallery, can you tell which flower is which type?

Hints - One photo is merely a representative clone of a species - almost like the "free space" on a Bingo card. One is a selected, named clone of a species. The other four are named hybrids. In alphabetical order, so you do have to figure out which name belongs with each picture: