The Armanen row is an early twentieth-century construction published by Guido von List in 1908, built from historical characters with his own names and meanings attached.
The character behind it
Bar corresponds to the Younger Futhark character whose Old Norse name was bjarkan, the birch. The rune poems gloss it as the birch or the birch twig, greenest of trees, and the association is stable across the Norse tradition. The character is common in Viking-age inscriptions as the letter B.
What von List did with it
He shortened the name to Bar, kept the B value, and gave the character a meaning within his eighteen that draws on birth and becoming rather than on the tree. The shift from a named tree to an abstract principle is typical of what the Armanen row does to its sources: the historical rune names are overwhelmingly concrete, and von List's readings overwhelmingly are not.
The frame
Von List presented the eighteen as an ancient Germanic priestly alphabet he had recovered, with the count matched to the eighteen rune-charms of the Havamal. No attested futhark has eighteen characters, and runologists treat the row as a construction of its own period.
Reception
The row was taken up in volkisch circles and, in the 1930s and 1940s, by National Socialist organisations. The atlas records that history plainly.