Keys to species Giffordia

1. Plants minute, about 5 mm tall
G. rallisae
1. Plants larger, often several centimeters tall
2
2. Branches often arcuate near their tips, the branchlets pectinate, secund
G. sandriana
2. Branchlets not pectinate
3
3. Plants about 2 cm tall, the gametangia scattered, usually more than 5 diameters long
G. duchassaigniana
3. Plants much larger
4
4. Gametangia to about 5 diameters long, more or less cylindrical, the tips blunt
4. Gametangia about 2 diameters long, conical
G. conifera