Gilfillan went to school in
Cradock, Eastern Cape, where his father Edward practised as a solicitor. After serving as an
articled clerk in the
Cape Town law firm of Reid & Nephew, he was admitted as a
solicitor and
notary to the Supreme Court of the Cape Colony. When the Boer War ended Gilfillan was appointed a member of the special criminal court for Johannesburg and acting magistrate for Boksburg and Germiston. Gilfillan collected over 500 botanical specimens. These were collected in the areas around Johannesburg (1898- 1899),
Middelburg, Eastern Cape (1899),
Heidelberg, Gauteng and
Witbank (1905). Gilfillan sent his specimens to Galpin, who incorporated them in his herbarium under Gilfillan's name. Galpin's herbarium later formed the nucleus of the government herbarium in
Pretoria. == Commemoration ==