Color-enhanced Scanning Electron Micrograph (SEM) of Milkweed (Asclepias L.) fibers. The milkweeds are a genus of herbaceous perennial, dicotyledonous plants that contains over 140 known species. Their floss is harvested to help fill pillows, comforters and stuff into jackets. The seeds, which are arranged in overlapping rows, bear a cluster white, silky, filament-like hairs known as the coma (often referred to by other names such as pappus, "floss", "plume", or "silk"). The follicles ripen and split open, and the seeds, each carried by its coma, are blown by the wind. Image width: 128 micrometers. Magnification: 780x if the image is printed 10 cm wide. Bar: 20 micrometers.