Bryophyte (moss) genome obviously is the most reliable. But you can identify mosses using a key that details things such as:

Is the gametophyte colony dark green or greyish-white in appearance?

Is the mature spore capsule upright or nodding?

When dry, do the leaves twist around the stem or simply fold inwards to the stem?

Does the leaf have a nerve or not ?

Are the cells in the lower leaf corners markedly different from the other leaf cells?

How large are the spores?

Lichens are not really plants – they are a combination of fungi and algae and are classified based on the fungus and fungal features. In order to identify lichen to species level, lichenologists use common household chemicals and some not-so-common chemicals to test the color reaction of the unique compounds found in the structure of the lichen, as well as using a lichen key to distinguish between species.

Please go through attached file and the links given below for the same.

http://fresc.usgs.gov/products/papers/1297_Woodward.pdf

http://wgbis.ces.iisc.ernet.in/biodiversity/sahyadri_enews/newsletter/issue34/reports/mosseslichenspop00marsrich.pdf

Drs Sarvade and Pegman,

Thanks for the contributions. They are well taken.

If you look into some of the chemical tests which you might need to do to identify to species level, some of them are very simple. It depends on what you are identifying, but for some I only needed a simple bleach solution to tell the species apart.

Thanks Erin for your contribution