Magnitude serves better than order to classify elongated systems and is more descriptive for small streams. Biota Streams can be divided into zones from the mountain headwaters to the estuary. Different zones support distinct biotic assemblages which lend themselves to descriptive names for the zones. Headwaters Streams are small, often intermittent streams which usually do not support fish. They are populated by insects, particularly mayflies, caddisflies, stoneflies, blackflies, and midges.
Plants consist mostly of benthic algae, mostly diatoms.
Bluegreen bacteria, particularly Nostoc , and mosses, such as Fontinalis ,may also be common producers in headwaters streams. Trout Streams , of course, are characterized by the presense of salmonid species. The same insects found in the headwaters are here. For a further description of trout streams see the ichthyology lecture on trout streams. Minnow Streams , in the British classification would equate to Native Cyprinoid Streams in North America since here the sucker family replaces Eurasian sucker-mouthed minnows.