Identification notes
To stand a chance of finding this scarce little moss you will need to be prepared to get muddy, to climb around in a tree hanging over a river, or both. O. sprucei is a member of the rather specialised community of mosses and liverworts that grow on the trunks, branches and exposed roots of trees on the banks of silty lowland rivers which rise over their banks quite regularly.
On riverbank trees and shrubs, there is often a vertical zonation of species over a metre or more. At the bottom of the zone, covered most frequently by rising and falling water, are the likes of Fontinalis antipyretica, Cinclidotus fontinaloides and Fissidens crassipes. At the top, generalist epiphytes such as Orthotrichum diaphanum and Lewinskya affinis can cope with occasional inundation for short periods. O. sprucei is found in the lower part of the zone, often with Syntrichia latifolia and Leskea polycarpa, on intermittently inundated branches close to normal water level. In some rivers, it is particularly fond of crack-willows growing on sediment berms where it may become quite silt-covered.
Although it has the same blunt leaves as O. rivulare, O. sprucei is a much smaller plant and there is normally no problem distinguishing it.
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