USA Biology Olympiad (USABO) Practice Exam

Which of the following groups of plants has vascular tissue but does not produce seeds?

1. Mosses

2. Ferns

3. Gymnosperms

4. Angiosperms

The correct answer is: Ferns

Ferns are indeed the correct choice because they represent a group of vascular plants that reproduce through spores rather than seeds. They belong to the group known as pteridophytes and are characterized by the presence of vascular tissues—xylem and phloem—which allow for the transport of water, nutrients, and food throughout the plant. Unlike seed-producing plants, ferns have a distinct life cycle that includes a dominant sporophyte generation and a gametophyte generation. The sporophyte produces spores within structures called sporangia, which are often found on the underside of the leaves in clusters known as sori. When these spores are dispersed, they can germinate into gametophytes that eventually produce gametes for fertilization. Mosses are non-vascular plants, so they lack vascular tissue. Gymnosperms and angiosperms, on the other hand, are both seed-producing plants, with gymnosperms producing naked seeds and angiosperms producing seeds enclosed in fruits. Thus, ferns stand out as the only group listed that has vascular tissue but does not produce seeds.