The bluebell is the first plant illustrated. The colours are not true in the 1902 edition I bought (seen on the right). The Charlecote 1855 edition is much more true to life. However a little colour adjustment in PaintShop brings the blue back and it resembles the 1855 edition so I suspect the image was true when printed but that the blue pigment used in the 1900s was different and has faded with time. Other colours seem unaffected.

This is what Anne Pratt has to say about the Bluebell:
Every child who has wandered in the woods, in the sweet months of April and May, knows the Blue-Bell, or Wild Hyacinth. Scarcely a copse can be found throughout our land which is not then blue with its flowers, for it is to the woodland and the green lane, in spring, what the buttercup is to the meadow. Growing near it we often find the beautiful pinkish-white blossoms of the wood-anemone, and before it fades away the hedges are getting white, and become fragrant with wreaths of the blooming May; but the primroses have almost all departed, and the violets are daily more rare.
The root of the wild hyacinth is round, and full of poisonous, clammy juice; indeed every part of the plant gives out more or less of this juice if we bruise it. Though the root is unfit for food, and is useless to us now, yet in former times it was much prized. In days when very stiff ruffs were worn, the juice was made into starch, and employed to stiffen the linen. It served the bookbinder, too, as glue, to fasten the covers of books. The flower has a slight scent, but the chief charms of the blue-bell are its beauty and its early appearance. It was but lately that we looked upon bare trees, and ground strewed with withered leaves and no songs of joy were heard; and now the early flowers seem to say, in the language of Scripture, “The winter is past; the rain is over and gone; the flowers appear on the earth; the time for the singing of birds is come; and the voice of the turtle is heard in the land.” Our wild hyacinth is sometimes found with white or flesh-coloured flowers but the beautiful garden hyacinths, with double blossoms, are bought from different countries of the East.