meaning of the name "Dictyostelium discoideum" _Dictyostelium discoideum_ is a well-known species of slime mould. Does anyone know what the name means? Here's my best guess. I found the 1935 article in which it was first described, but there doesn't seem to be an explanation for the species name 'discoideum'. It might mean 'disk shaped', as in disk+oid plus an agreement morpheme -eum, because in Picture A in plate I, the sorocarp is described as having an 'expanded basal disk'. The genus name 'dictyostelium' seems to be a reference to the stalk of the sorocarp, and how it resembles a 'dictyostele' or fern stem ('dictyo' meaning 'mesh' + 'stele' meaning upright stone), which seems plausible but strange, because I don't think the stalk has any internal structure like an actual dictyostele. So if that's right, the overall name would be a physical description of the fruiting body, something like 'thing with a fern-like stem on a disk-like base'. Is any of that even close?

I think your analysis is correct.

_Dictyostelium_ generally means net-like pillar. _Dictyo_ references a net or mesh, and stele originates from the Greek _stēlē_ : to stand or pillar. However, as you point out, "stele" is also the word for the central vascular tissue in vascular plants. The stele can take on several different architectural arrangements, including a net, or dictyostele, in some ferns.

As I don't read German either, it's unclear to me if Brefeld was referencing the structure in ferns, or just describing _D. mucoroides_ on its own terms, perhaps envisioning the gathering of cells to form the stalk as being like a net. See, for example, this image of a _Dictyostelium_ aggregation.

!an aggregation of Dictyostelium forming a stalk

"Discoideum," as you note, means "disk-shaped," and Raper in his description references "expanded disklike bases" and "basal disks."