Streptocarpus muscosus is one of the interesting Madagascan Streptocarpellas, with relatively large and soft leaves with small white flowers. It is caulescent but seldom grows fully upright, being more typically found as a low creeping plant. In the feature plant above the creeping stems can be seen even while the central stem appears to be more upright.
S. muscosus can be easily confused with Streptocarpus thompsonii, which is also endemic to Madagascar and whose range overlaps. Useful features for separating the species include the following:
- The flowers of S. thompsonii are an open tube type, tapering to the calyx; those of S. muscosus have a distinct pouch shape on the lower corolla, creating a more rounded look below
- The stems of S. thompsonii are usually mottled with maroon or purple spotting, while those of S. muscosus are unspotted
- S. thompsonii is, in general, relatively upright and shrubby, while S. muscosus tends to be more sprawling, with stems creeping along the soil or moss; as noted, thompsonii can be much smaller in some circumstances, and then more resembles the habit of muscosus
