This collection includes letters between Peter René Oscar Bally and Gilbert W. Reynolds (1895–1967), an optician in Johannesburg, and later of Swaziland. Reynolds was a collector of and authority on the genus Aloe Linnaeus. The correspondence concerns Reynolds’ Aloes of South Africa (1950), as well as the travel and collecting of Aloe specimens done by both men, including Reynolds’ work for Aloes of Tropical Africa and Madagascar (1966) and Bally’s for The Genus 'Monadenium,' A Monographic Study (1961). Most of these letters are one to two pages in length, and were sent from Johannesburg, Nairobi, Switzerland, Kew, or Swaziland. Also included in this collection are lists of Aloe species and their localities shared between Bally and Reynolds, as well as Airway bills for the consignments of plants they would send one another. In addition, there is a letter of condolence from Bally to Reynolds’ widow, Kathleen, (copy, 26 April 1967) and her reply (June 1967).