The genus Streptopogon is typically corticolous, reddish in color, and often has densely tomentose stems that lack a central strand. Its leaf cells are smooth, the costa has a single (dorsal) stereid band, and vegetative propagula are commonly found on the leaves. Sporophytically the genus has thick, cylindrical capsules, long, filamentous, spirally-twisted peristome teeth, and a large conic-mitrate (often scabrous-prorulose) calyptra. The genus is similar to Scopelophila in color, stem cross-section, leaf cell ornamentation, and costal morphology. Scopelophila differs from Streptopogon in its terricolous or saxicolous habit, sparsely distributed rhizoids, eperistomate capsules, and cucullate calyptrae.

Although the stems in Streptopogon are often densely tomentose it has relatively few rhizoidal initials. The thickly tomentose stems are the result of its densely branched (often at right angles) rhizoids. All species of Streptopogon have peristomes with fragile basal membranes and as a consequence the peristomes are often detached below the capsule mouths. Collections with only old capsules may appear gymnostomous because of this type of peristome loss.