She was fascinated by the chapters on the structure of plants and the Linnean classification system, and responded to the author's request for specimens so that he could begin documenting the flora of the Cape.

[3] Her ongoing correspondence with Harvey took place during a time when it was not generally accepted for women to engage in scientific discussion;[4] indeed, in the beginning she did not disclose the fact that she was a woman.

[7] She and her younger brother, naturalist James Henry Bowker, sent many previously unknown species of plants to the herbarium at Trinity College Dublin, and the Royal Botanic Gardens in Kew.

With her brother, James Henry Bowker, she began documenting African moths and butterflies, and contacted entomologist Roland Trimen (1840–1916) in 1863 to share her discoveries.

[4] In other letters, Barber seemed to concur with Darwin's theory of natural selection, citing the dominance of European settlers in Cape Colony as proof.

[11] Barber's contributions to science were eventually rewarded in 1878 with an invitation to become a member of the South African Philosophical Society – a singular honour at the time.

I do not by any means approve of ladies coming publicly forward and usurping the places of men by preaching, making speeches, etc., but I don't see why they should not belong to any society that they are qualified for, and in a quiet way enjoy the privileges too."

[13] Barber fully appreciated (and had the observations to prove) that females choose males based on their phenotypes: showy courtships, glossy plumage.

[4] In the 1850s Barber assisted her older brother, Thomas Holden Bowker, in his work amassing the first collection of Stone Age implements in South Africa.