calyptrogen Bot.
(kəˈlɪptrədʒɛn)
[f. Gr. καλύπτρα covering + -gen taken in sense of ‘producer’.]
The outer zone or layer of the meristem or primary tissue of the youngest part of plants.
| 1881 Nature XXIII. 288 Four zones of meristem:—calyptrogen, dermatogen, periblem and plerome. 1884 Bower & Scott De Bary's Phaner. & Ferns 9 Since this accession originates in certain cases from a special layer of meristem, the latter is to be distinguished as the calyptrogen. |