Caption: Charles Darwin's (1809--1882) first diagram of a phylogenetic tree (AKA evolutionary tree) or tree of life in Notebook B: Transmutation of species (1837--1838), p. 36.

From the hand of the creator so to speak.

The handwriting interpreted:

I think (sketch) Case must be that one generation then should be as many living as now. To do this & to have many species in same genus (as is) requires extinction. Thus between A & B immense gap of relation. C & B the finest gradation, B & D rather greater distinction. Thus genera would be formed.---bearing relation

---Charles Darwin (1809--1882), Notebook B: Transmutation of species (1837--1838), p. 36.