Gnetophytes

Definition

Gnetophytes are a group of gymnosperms comprising three distinct genera: Ephedra, Gnetum, and Welwitschia. They are unique among gymnosperms for their vessel elements similar to those found in angiosperms.

5 Must Know Facts For Your Next Test

1. Gnetophytes have three genera: Ephedra, Gnetum, and Welwitschia.
2. They possess vessel elements in their xylem, which is uncommon in other gymnosperms.
3. Welwitschia mirabilis, found in the Namib Desert, has only two leaves throughout its life.
4. Ephedra is known for containing ephedrine, a compound used in traditional medicine.
5. Gnetophytes exhibit double fertilization similar to that of angiosperms but result in two embryos instead of one embryo and an endosperm.

Review Questions

• What are the three genera that make up gnetophytes?
• How do gnetophytes differ from other gymnosperms in terms of their vascular tissue?
• What unique characteristic does Welwitschia mirabilis have regarding its leaves?

Related terms

Gymnosperms:

Seed-producing plants that do not form flowers or fruits; includes conifers, cycads, ginkgoes, and gnetophytes.

Angiosperms:

Flowering plants that produce seeds enclosed within a fruit.

Vessel Elements: Specialized cells in the xylem of angiosperms and some gymnosperms like gnetophytes that facilitate water transport.