These virtually identical prints are clearly from two different publications. The Curtis (above left) is the original, with the Van Houtte being the copy, some time later.
Note the differences. The prints are mirror images, a function of copying the original onto an engraving plate, with the effect of mirroring the final product. The cut-off leaf to the upper right of the Curtis has been created with a bent form to allow it to fit in the plate in the Van Houtte, at upper right. The color is also subtly different, with the Curtis flowers having a more maroon calyx, as distinct from the purple of the Van Houtte. The red veining of the leaves is also more pronounced in the Curtis.