Selaginella

Definition

Selaginella is a genus of seedless vascular plants commonly known as spikemosses, belonging to the group of plants that reproduce via spores rather than seeds. This genus includes various species that are adapted to diverse habitats, and they are characterized by their unique leaf arrangements and the presence of strobili, which are cone-like structures that bear spores. Selaginella plays an important role in understanding the evolutionary transition from non-seed vascular plants to seed-bearing plants.

5 Must Know Facts For Your Next Test

1. Selaginella is notable for its ability to survive in harsh conditions, including drought, by entering a state of desiccation and reviving when water becomes available.
2. There are over 700 species of Selaginella, demonstrating a wide range of adaptations to different environments, from tropical rainforests to arid regions.
3. Selaginella exhibits heterospory, producing two distinct types of spores: microspores and megaspores, which lead to the formation of male and female gametophytes respectively.
4. The leaves of Selaginella are small and scale-like, often arranged in a spiral pattern around the stem, providing an efficient method for water retention and photosynthesis.
5. Selaginella is sometimes referred to as a living fossil due to its ancient lineage and similarity to early vascular plants that dominated the Earth millions of years ago.

Review Questions

• How does the reproductive process of Selaginella differ from that of flowering plants?
  • Selaginella reproduces using spores instead of seeds, which is a key difference from flowering plants. In Selaginella, the life cycle involves the production of strobili that bear spores. These spores develop into gametophytes, where fertilization occurs. In contrast, flowering plants produce seeds after fertilization takes place within flowers, representing a more advanced reproductive strategy.
• Discuss the ecological significance of Selaginella in its native habitats.
  • Selaginella plays an important ecological role in its native habitats by contributing to soil stabilization and providing cover for other plant species. Its ability to survive in diverse environments allows it to occupy niches that might be challenging for other plants. Additionally, its presence can enhance biodiversity by offering microhabitats for various organisms and participating in nutrient cycling within ecosystems.
• Evaluate the evolutionary importance of Selaginella in understanding the transition from non-seed vascular plants to seed-bearing plants.
  • Selaginella is crucial for evaluating the evolutionary history of land plants due to its position within the lycophytes group. It showcases characteristics that link early vascular plants with more advanced seed-bearing plants. The study of Selaginella’s unique reproductive strategies and structural features provides insight into how plants adapted over time to terrestrial environments. Understanding these transitions helps clarify the evolutionary pathways leading to the diversity of plant life we see today.

Related terms

Lycophytes: A group of ancient vascular plants, including Selaginella, known for their microphylls and ability to reproduce via spores.

Strobilus: A reproductive structure found in certain plants, including Selaginella, that bears spores and resembles a cone.

Spores: Reproductive cells produced by seedless vascular plants like Selaginella, which can develop into a new individual without fertilization.