Thin-walled spores produced by the uredium
Urediniospores of 11 Milesina species. a Milesina blechni on Struthiopteris spicant b Milesina blechni on Struthiopteris spicant , cracked spore with released plasma, germ pores scattered c Milesina carpatica on Dryopteris filix-mas d Milesina exigua on Polystichum braunii , smooth surface e Milesina exigua on Polystichum braunii , smooth surface, plasma-free spore, germ pores bipolar f Milesina feurichii on Asplenium septentrionale with smooth areas on surface g Milesina feurichii on Asplenium septentrionale , cracked plasma-free spore, germ pores scattered h Milesina kriegeriana on Dryopteris carthusiana i Milesina magnusiana on Asplenium adiantum-nigrum with smooth areas on surface j Milesina magnusiana on Asplenium adiantum-nigrum , spore plasma-free, germ pores scattered k Milesina murariae on Asplenium ruta-muraria with smooth areas on surface l Milesina murariae on Asplenium ruta-muraria , cracked spore with released plasma, germ pores scattered m Milesina polypodii on Polypodium vulgare with smooth areas on surface n Milesina scolopendrii on Asplenium scolopendrium with smooth areas on surface o Milesina vogesiaca on Polystichum aculeatum , surface with very flat warts at the tip of the spore (arrow) p Milesina vogesiaca on Polystichum aculeatum , surface smooth (no warts visible at the tip), germ pores bipolar q Milesina whitei on Polystichum sp. r Milesina whitei on Polystichum setiferum , cracked spore with released plasma, germ pores scattered.
Urediniospores (or uredospores ) are thin-walled spores produced by the uredium , a stage in the life-cycle of rusts .
Development Urediniospores develop in the uredium , generally on a leaf's under surface.
Morphology Urediniospores usually have two dikaryote nuclei within one cell. In mass they are usually pale brown in contrast to teliospores which are generally dark brown.
See also
References C.J. Alexopolous, Charles W. Mims, M. Blackwell, Introductory Mycology, 4th ed. (John Wiley and Sons, Hoboken NJ, 2004) ISBN 0-471-52229-5