Note: Key to 5 of 7 species.
1. Leaves without hyaline border or hyaline cells at leaf apices; on various substrates …2.
1. Leaves with hyaline border (at least a few hyaline cells present on the leaf apices of most leaves); plants almost always epiphyllous …3.
2. Lobules almost as long as the lobe; plants very small (to 600 um wide); leaves suborbicular … C. minutissima
2. Lobules much shorter than the lobe; plants; leaves ovate to rounded, less than 2 times longer than wide … C. obliqua
3. Hyaline border entire, composed of 1-3 rows of rectangular cells, finger-like cells at leaf apex lacking … C. subscariosa
3. Hyaline border with 1 row of finger-like, projecting cells at leaf apex lacking … 4.
4. Lobules large, keel more than 1/3 of the lobe length; hyaline cells restricted to the lobe apex … C. cardiocarpa
4. Lobules small, keel less than 1/4 of the lobe length; hyaline border often extending to midleaf … C. verwimpii