How do lycophytes reproduce without seeds or flowers?

Lycophytes reproduce through an alternation of generations, cycling between a spore-producing sporophyte and a sex-cell-producing gametophyte. Because they lack seeds and flowers, they rely on these distinct phases and the presence of water for fertilization.12

The reproductive process varies by group:

• Homosporous Lycophytes: Genera such as Lycopodium produce one type of spore. These spores germinate into bisexual gametophytes that produce both sperm and eggs. Once mature, flagellated sperm swim through a film of water to reach the egg-producing archegonia for fertilization.12
• Heterosporous Lycophytes: Genera such as Selaginella and Isoetes produce two types of spores: small microspores (which develop into male gametophytes) and large megaspores (which develop into female gametophytes). These gametophytes are microscopic and often develop within the spore wall. Fertilization occurs when sperm swim to the archegonia on the female gametophyte.12

In both cases, the resulting embryo grows into a new sporophyte, eventually becoming independent of the gametophyte.12