Few people give much notice to the seedless vascular plants, partly because they are small, and partly because of lack of knowledge about them. Do a "show and tell" demonstration of the seedless vascular plants, allowing students to examine them individually.
Show examples of Marchantia with its archegoniophores and antheriodiophores and Mnium or similar moss species with its archegonial heads. Demonstration specimens of a variety of ferns and prepared slides of fern prothalli are useful in illustrating the stages of a fern life cycle.
Once students notice the unique adaptations of these groups, they gain understanding and interest in them.
Go to a local florist, or the campus greenhouse, and select several common flower specimens that show pistils, stamens, anthers, and several petal formations (species will vary with availability and season). Allow students to dissect the flowers, and help them identify parts, discussing the adaptations of a particular floral shape as you proceed.