It is lighter in color than nimbostratus and darker than high cirrostratus. Cirrostratus fibratus is a type of cirrostratus cloud. These are made when the cloud takes the form of thin cirrostratus nebulosus. Cirrostratus nebulosus is a species of high-level cirrostratus cloud. Cirrus radiatus is often partly made up of cirrocumulus or cirrostratus. Clouds resembling cirrostratus occasionally form in polar regions of the lower stratosphere. The other clouds in this level are cirrus and cirrostratus. The other two genera, cirrocumulus and cirrostratus, are also high clouds. There are three main genera in the family of high clouds&colon; cirrus, cirrocumulus, and cirrostratus. The cloud has a fibrous texture with no halos if it is thicker cirrostratus fibratus. The name "cirrostratus fibratus" is derived from Latin, meaning "fibrous". Of the stratiform group, high-level cirrostratus comprises two species. Cirrostratus "nebulosus" has a rather diffuse appearance lacking in structural detail. Cirrostratus fibratus may often develop from either cirrus fibratus or cirrus spissatus cloud.