Fertile shoots possess sessile strobili, borne at the tops of their main axes and sometimes at the tips of dominant lateral branches.

Identifying D. obscurum in the wild can be difficult without prior study, because it is not only relatively rare, but shares much of its morphology with D. dendroideum and D. hickeyi.

All underground branching occurs parallel to the ground, so upright shoots must then orient themselves appropriately in order to emerge from the soil.

[14] The age of a shoot corresponds to the layers of compressed microphylls in its stem, caused by growth halting each winter, the same way as tree rings are formed.

Second year shoots undergo rapid growth, usually reaching near their final heights, and forming several systems of lateral branches.

[16] Historically, Dendrolycopodium obscurum has been harvested from the wild for use as Christmas greens for wreaths, as well as the use of its spores for flash powder.

While flash powder is now practically obsolete, the harvest of D. obscurum has caused it to become threatened in several areas, leading Indiana[1] and New York[3] to declare it protected by state law.

When harvesting legally, it is recommended to cut the shoots using shears to minimize rhizome damage, alternate sites every year, and select only individuals possessing strobili with open sporophylls.