These are the predominating gradations, but there are occasional blues and mineral greens, passing into olive, but no pure or chlorophyllous green.

Around every vascular bundle there is a single row of somewhat large cells densely packed with large chloroplasts, the chlorophyllous layer.

I find in an old note book of my father's, dated 1879, "chlorophyllous matter in leaves encouraged by electric energy, presumably by the blue rays."