{{Short description|Thin-walled spores produced by the uredium}} {{Use dmy dates|date=October 2023}} {{one source|date=October 2023}} [[File:Milesina (10.3897-mycokeys.48.30350) Figure 6.jpg|thumb|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== {{Portal|Fungi}} *Chlamydospore *Urediniomycetes *Pycniospore *Aeciospore *Teliospore *Ustilaginomycetes *Rust fungus: Spores
==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}}
Category:Germ cells Category:Fungal morphology and anatomy Category:Mycology
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