An organ, structure, or tissue in the earliest stage of development.
- ‘In flowers, both genes are expressed throughout inflorescence and floral meristems and in developing organ primordia.’
- ‘Although mitoses were still detected in leaf primordia of that stage, cell differentiation had already started.’
- ‘The development is initiated as a hyphal knot of 0.2 mm or less in diameter, which rapidly develops into a tiny primordium containing the rudimentary tissues of the future pileus and stipe.’
- ‘These organ primordia, which develop after a period of time corresponding to winter in temperate regions, are called preformed organs.’
- ‘Microscopical examination for the fungal infection was performed on the bristles, adjacent hypocotyl surface and the internal tissue of root primordia.’
Late 19th century: from Latin, neuter of primordius original from primus first + ordiri begin.