Magazine of Horticulture 8: 134-135 (April 1842)
Art. IV. Some notice of a new variety of the Michigan Rose, (Rosa rubifolia)
By An Amateur

Perpetual Michigan; pink, changing to purple; cupped, and very double; flowering from three to four times a year.

Should ‘Detroit’, ‘;Michigan’, ‘Michigan Perpetual’ and ‘Perpetual Michigan’ (http://www.helpmefind.com/gardening/l.php?l=2.33029.3&tab=1) be merged with
‘Perpetual’, ‘Purpurea’, ‘Perpetual Pink’
(http://www.helpmefind.com/gardening/l.php?l=2.33032.0)
The 1844 reference for ‘Perpetual Pink’ mentions a synonym of ‘Perpetual Michigan’.

Magazine of Horticulture, 10: 246-248 (July 1844)
Art. II. Descriptions of Mr. Feast's Seedling Rubifolia or Prairie Roses. By the Editor.
Perpetual Pink.—Synonyme. Perpetual Michigan. Flowers, medium size, rosy purple changing to rose, cupped and very double, resembling in shape the multiflora. Clusters, large, containing from ten to twenty blooms; foliage, nearly smooth, very dark green; spines, rather strong and thick, forming quite a pubescence on the peduncles of the flowers; growth, vigorous. How far this will prove a perpetual bloomer remains to be tried; we saw it flowering a second time in Mr. Feast's garden, in Oct. 1843, though its habit of continual blooming may be quite uncertain.