Tetragonia hirsuta, a red fruit

The four-winged Tetragonia hirsuta fruits or samaras may become red, as is happening on this plant in the Biedouw Valley during September. The Afrikaans common name, grootsaadklappiesbrak (big seed tetragonia), is warranted. 

The very noticeable fruit-shape reminds of turbine blades but it is membranous, soft and fleshy while green. The fruit surfaces are coarse, covered in large surface cells and sometimes shiny. The seed is borne in the centre where the wings converge. 

The dry perianth remains at the fruit tips in picture are dark brown, spreading again after a period of being closed. They will later drop off (Le Roux, et al, 2005; Bond and Goldblatt, 1984; JSTOR; iNaturalist).