aitnorth's Favorites

Black mass of very dark filamentous cyanobacterial threads, growing on a shaded and sheltered limestone face. Easily peeled off from surface in exfoliating flakes. The rock face is a solid slab, but the surface under the flakes is composed of rock dust. To me this implies a possible metabolic weathering of the rock slab by the bacteria.

The filamentous mass is densely and closely associated with what looks like a Gleocapsa species, and this seems to be the cause of the 'bluer' sections of the peeling flakes (photo #2). I took two sections of the flakes for microscope analysis, one of the pure dark threads and one of the black mass covered in the blueish dust. There was more of the Gleocapsa in the blueish section of the flakes by an order of magnitude or so.

This observation is tightly associated with Lempholemma cladodes, a tiny lichen that was growing in the limestone rock dust underneath and among the Scytonema filaments. See that observation here: https://www.inaturalist.org/observations/43124032

Growing on top of a mound of limestone rock dust on a very shaded and sheltered limestone rock ledge. The thallus has an iridescent sheen to it, which it turns out isn't an illusion - see the microscope photos for the (frankly alarming) shade of purple some of the cells are. Sometimes they break off and are freely floating in the slide.

To my knowledge (iNat and Sask records), this species has not been found within the province north of the South Saskatchewan River. This location seems to be a truly unique spot, harbouring species well north of their typical range including Smooth Sumac (Rhus glabra).

Apothecia turning a brilliant deep purple in KOH, spores polarilocular, 17.7 x 8.8 micrometres. Septum up to 3.5 micrometres. Growing on moss in sheltered, humid site on ledges of limestone rock. Apothecia 0.5-1.2 mm.