Definition of "cryptogam"

In the absence of phanerogams, the cryptogams — principally the algae, mosses, and lichens — are the dominant forms of plant life.

1956, George A. Llano, Botanical Research Essential to a Knowledge of Antarctica, A. P. Crary, L. M. Gould, E. O. Hulburt, Hugh Obishaw, Waldo E. Smith (editors), Antarctica in the International Geophysical Year, Geophysical Monograph Number 1, American Geophysical Union, page 124

Not only were bromeliads and orchids covering the exposed bark of the trees, the dominant diminutive cover (known as epiphylls) was composed of cryptogams, small plants that lack true flowers and reproduce with spores.

1999, George O. Poinar, Roberta Poinar, The Amber Forest: A Reconstruction of a Vanished World, page 36

The first vascular plants to develop were vascular cryptogams reproduced using spores and, today, such plants can still be found as the herb families of club mosses, ferns, horsetails and in fern trees.

2011, Göran Gellerstedt, Gunnar Henriksson, “9: Lignins: Major Sources, Structure and Properties”, in Mohamed Naceur Belgacem, Alessandro Gandini, editors, Monomers, Polymers and Composites from Renewable Resources, page 201