This species occurs at a higher altitude than any other Aylostera, as high as 4400m. It occurs over several hundred square kilometres, and within that range varies considerably and gradually, so over time many variations have been recorded as separate species. Mosti and Papini (2011) have rationalised this through field studies and as part of the work on DNA, and proposed that some are indeed different enough to be given specific status. Among these are “Aylostera atrovirens var. ritteri” which is now Aylostera ritteri. However A. atrovirens is a species “group” for which the species concept doesn’t really work- there are clines of variation throughout the area, in some places even converging in appearance to be like A. pygmaea, although the two species are still distinguishable and don’t seem to hybridise where they occur in the same area.
The plant is quite distinctive, being dark glossy green with purplish tones, and squat, almost as wide as it is high (which I guess makes sense for a high altitude plant) with decurved spines. Flowers vary from a distinctive bright carmine red to lighter reds.
The original description of Lobivia (Aylostera) atrovirens is here.
Plants of this species in the collection include:
Aylostera atrovirens MN134
Aylostera atrovirens NL78
Aylostera atrovirens RH1386
Aylostera atrovirens RH2412
Aylostera atrovirens RH3133
Aylostera atrovirens RH864
Aylostera atrovirens RH866