 Remarkable about Darwin’s diagram of the tree of life is the relativity of its coordinates. It is first presented as applying only to the divergences taking place at the varietal level, with varieties represented by the small lower-case letters within species A–L of a “wide ranging genus”, with the horizontal time coordinates measured in terms of a limited number of generations. However, the attentive reader could quickly see that Darwin’s destructive analysis of the distinction between “natural” and “artificial” species and the relativity of the species-variety distinction, worked out in chapter two, allowed this diagram to represent eventually all organic relationships, from those at the non-controversial level of diverging varieties within fixed species, to those of the relations of species within different genera. Letters A–L could also represent taxa at the level of Genera, Families or Orders. The diagram can thus be applied to relationships between all levels of the Linnaean hierarchy with the vertical coordinates representing potentially vast expanses of time, and the horizontal coordinates the degree of taxonomic divergence over time. In a very few pages of argument, the diagram was generalized to represent the most extensive group relations, encompassing the whole of geological time. Extension of the dotted lines at the bottom could even suggest, as Darwin argues in the last paragraph of the book, that all life was a result of “several powers, having been originally breathed into a few forms or into one” (Origin 1859: 490). This could suggest a naturalistic origin of original forms either by material emergence, or through the action of a vitalistic power of life. It could also be read as implying the action of a supernatural cause.