Cryptogams and Gymnosperms: Ancient Lineages and Their Marks
Algae, bryophytes and pteridophytes
Know algal groups by pigments, storage products and cell wall composition, and the alternation of generations in each. For bryophytes, understand the dominant gametophyte, the dependent sporophyte, and the ecological role of Sphagnum. For pteridophytes, learn the dominant sporophyte, the independent gametophyte, homospory versus heterospory, and the rise of the seed habit.
Gymnosperms
Understand the life cycle of Pinus and Cycas, the structure of the strobilus, the difference between male and female cones, and the nature of the ovule and seed. Learn the major gymnosperm groups - cycads, ginkgo, conifers, gnetophytes - and their economic and evolutionary significance.
Traps
Questions often reverse the dominant generation, or confuse the protonema with the prothallus. Another trap is treating the gymnosperm ovule as enclosed in an ovary; it is naked. Watch for questions on heterospory and the origin of the seed habit.
Rule of thumb
For any cryptogam, state the dominant generation, the gametangia, the spore type and the dependence relationship. This framework answers most life-cycle questions.
Worked example
In a moss, the green leafy plant is the gametophyte; the stalked capsule is the sporophyte, dependent on the gametophyte for nutrition.