Vertical intervallar structures: Longitudinal and often radial structures inside the intervallum (septa, taeniae...).
Intervallum: Space enclosed between the walls.
Septum (plur. septa): Planar porous partition linking both walls of a two-walled cup with a radial-longitudinal distribution
Pseudoseptum: Planar or slightly waved irregularly porous partition linking both walls of a two-walled cup with a radial-longitudinal distribution.
Taenia (plur. taeniae): Intervallar porous structure, non-planar, often dichotomous with a radial-longitudinal distribution.
Dictyonal network: Three-dimensional intervallar structure composed by taeniae with tetragonal pores linked by synapticulae at each interpore.
Taenia (plur. taeniae): Intervallar porous structure, non-planar, often dichotomous with a radial-longitudinal distribution.
Synapticula (plur. synapticulae): Narrow horizontal rod linking two adjacent vertical intervallar structures.