Peristomes

An interesting day spent at the BCN Wildlife Trust Monitoring and Ecology Conference, though it did seem a bit unfortunate to have to sit inside during such wonderful weather. 

No time for a walk after we got home, so I practiced taking photographs of very tiny things down the microscope. These are the surprisingly colourful and intricately structured spore capsules of a very common moss, Rhynchostegium confertum. 

Most mosses produce a capsule with a lid (the operculum) which falls off when the spores inside are mature and ready to be dispersed. The opening is called the stoma (meaning "mouth") and is surrounded by one or two peristomes. Each peristome is a ring of triangular "teeth" formed from the remnants of dead cells with thickened cell walls. There are usually 16 such teeth in a single peristome, separate from each other and able to both fold in to cover the stoma as well as fold back to open the stoma. The peristome allows for gradual spore discharge, instead of releasing them all at once. The peristome teeth are surprisingly mobile and almost seem to dance if you look at them long enough under the microscope.