Urediniospores (or uredospores ) are thin-walled spores produced by the uredium , a stage in the life-cycle of rusts .
Urediniospores of 11 Milesina Milesina blechni Struthiopteris spicant Milesina blechni on Struthiopteris spicant , cracked spore with released plasma, germ pores scattered c Milesina carpatica Dryopteris filix-mas Milesina exigua Polystichum braunii Milesina exigua on Polystichum braunii , smooth surface, plasma-free spore, germ pores bipolar f Milesina feurichii Asplenium septentrionale Milesina feurichii on Asplenium septentrionale , cracked plasma-free spore, germ pores scattered h Milesina kriegeriana Dryopteris carthusiana Milesina magnusiana Asplenium adiantum-nigrum Milesina magnusiana on Asplenium adiantum-nigrum , spore plasma-free, germ pores scattered k Milesina murariae Asplenium ruta-muraria Milesina murariae on Asplenium ruta-muraria , cracked spore with released plasma, germ pores scattered m Milesina polypodii Polypodium vulgare Milesina scolopendrii Asplenium scolopendrium Milesina vogesiaca Polystichum aculeatum Milesina vogesiaca on Polystichum aculeatum , surface smooth (no warts visible at the tip), germ pores bipolar q Milesina whitei Polystichum Milesina whitei on Polystichum setiferum
Urediniospores develop in the uredium , generally on a leaf's under surface.
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.
C.J. Alexopolous, Charles W. Mims, M. Blackwell, Introductory Mycology, 4th ed. (John Wiley and Sons, Hoboken NJ, 2004) ISBN 0-471-52229-5
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