Cladonia pleurata are part of the large family of pixie cups, club lichens that resemble tiny goblets.  The red color are apothecia (“a spore-bearing structure in many lichens and fungi consisting of a discoid or cupped body bearing asci on the exposed flat or concave surface”).

pixie cups

pixie cups

pixie cups

pixie cups

pixie cups

Similar looking lichens include cladonia cristatella or British soldiers, cladonia bellidiflora or toy soldiers, and cladonia macilenta or lipstick powderhorn.