Cross-section of nodule on Alnus glandulosa showing infected cortical cells (actinomycetes?) stained red; central red tissue are the vascular elements.

Microsection of Alnus nodule to show the infected cortical cells; n.b. the mycelia of the actinomycete which terminate in the vesicles. cf. slides # 213-217

Microsection of the cortical cells of an Alnus nodule to show the vesicles (stained red) within the cell which are thought to be the site of Nitrogen fixation

Algal growth on soil surface which is fixing Nitrogen

Close-up of the L, H,, Ah, Bm horizons in a Dystric Brunisol at Dorset.

Profile in a basal till (sandy loam) under mixed boreal forest; n.b. compaction lines in till; location Cairo Twp. in Plonski Forest near Swastika

Close-up of the basal till in slide #220, showing the "lenses" or lines of compaction in the till.

Profile of an orthic gray brown luvisol; n.b. light colour area to right in Ah is due to dry soil; Located at Dunlap Observatory woodlot Richmond Hill; same profile as slide #223.

Same profile as slide # 222, but from different angle; gray-brown luvisol

Root channel just below Bt, in Ck; in profile of gray-brown luvisol slide # 222 & 223