29.1. Publication is effected, under this Code, only by distribution of printed matter (through sale, exchange, or gift) to the general public or at least to botanical institutions with libraries accessible to botanists generally. It is not effected by communication of new names at a public meeting, by the placing of names in collections or gardens open to the public, or by the issue of microfilm made from manuscripts, type-scripts or other unpublished material.
Ex. 1. Cusson announced his establishment of the genus
Physospermum in a memoir read at the Société
des Sciences de Montpellier in 1770, and later in 1782 or 1783
at the Société de Médecine de Paris, but
its effective publication dates from 1787 (in Hist. Soc. Roy.
Méd. 5(1): 279).