This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Kurt Leland's book length documentary history, Rainbow Body, traces exactly how the modern Western seven chakra, rainbow colored scheme, and the gland correspondences attached to it, was assembled piece by piece across nearly a century rather than inherited whole from any single ancient source. Leland's account runs from Helena Blavatsky's earliest Theosophical writing on subtle centers, through Leadbeater's own 1927 clairvoyant description, and on through later contributors including Alice Bailey, Carl Jung and, more recently, Barbara Brennan, naming each writer's specific documented addition to the scheme rather than presenting it as one continuous unbroken transmission.
That documented history matters for a gland entry because the specific pairing of an endocrine gland with a given chakra is not part of any single early account, it is a layered later synthesis, and Leland's history lets an entry state honestly which part of a gland's esoteric meaning traces to an early contributor and which part entered through a later writer's own addition.
An entry therefore draws on Leland's documented history of transmission and revision for the correspondence scheme's actual assembly, while keeping any specific gland to chakra pairing sourced to the particular writer's own text that first states it, since treating the scheme as a single ancient teaching would misstate what kind of claim it actually is.