Although S. scorpioides superficially looks very different from the other two members of the genus, these differences are mainly found in characters, such as size and leaf shape, that affect the appearance of the plant to the naked eye. On the other hand, microscopic features of, e.g., stems, alar cells, and exostomes that are critical in understanding the relationships of this species are the same as in S. cossonii and S. revolvens . Scorpidium scorpioides is thus an example of a species with a number of autapomorphies that are easily visible to the naked eye, in a genus where the two other members have a more generalized appearance. Scorpidium is one of the genera of the Amblystegiaceae where red pigments are frequently present in at least parts of the plants. When they are mineral-rich they are mostly rich in calcium.
All species occur in North America.
The genera Scorpidium and Hamatocaulis , gen. Janssens, J. A. 1983. Past and extant distribution of Drepanocladus in North America, with notes on the differentiation of fossil fragments. J. Hattori Bot. Differentiation in habitat requirements within the genus Scorpidium , especially between S. revolvens and S. cossonii .