Sporid

Further North, where it [sc. rust] first attacks the barberry its primary form and color is a yellow cup-cell, which matures and sends out spores which attack the wheat by penetrating into its tissue, as the sporid did the brier, and produce the red, globular cell.

357. […] Somewhat later in the season the same parasitic filaments which have been producing Red-rust spores begin to produce lines or spots of dark-colored, thick-walled, two-celled bodies (teleutospores), the so-called spores of the Black-rust […] Being thick-walled, they endure the winter without injury, and when spring comes […] they germinate on the rotting straw and produce several minute spores, called sporids. This is the fourth and last stage of the rust. The sporids fall upon Barberry-leaves and germinate […] giving rise to cluster-cups again.

As the sporids originating from Micrococcus of sheep-pox develop, according to Hallier, in the air to a Cladosporium […]