The species "Cumulus fractus" is ragged in appearance and can form in clear air as a precursor to cumulus humilis and larger cumulus species-types; or it can form in precipitation as the supplementary feature "pannus" (also called scud) which can also include stratus fractus of bad weather. "Cumulus humilis" clouds look like puffy, flattened shapes. "Cumulus mediocris" clouds look similar, except that they have some vertical development. "Cumulus congestus" clouds have a cauliflower-like structure and tower high into the atmosphere, hence their alternate name "towering cumulus". The variety "Cumulus radiatus" forms in radial bands called cloud streets and can comprise any of the four species of cumulus.