Selaginella

Definition

Selaginella is a genus of plants commonly known as spikemosses, which are part of the family Selaginellaceae. These plants are considered ancient relatives of ferns and are categorized under seedless vascular plants, characterized by their small, scale-like leaves and ability to reproduce through spores rather than seeds. Selaginella species are often found in moist environments and are notable for their unique life cycle that includes both a gametophyte and a sporophyte generation.

5 Must Know Facts For Your Next Test

1. Selaginella is often referred to as 'living fossils' due to their ancient lineage that dates back over 400 million years.
2. These plants are unique among seedless vascular plants because they can survive extreme dehydration, entering a dormant state until conditions improve.
3. Selaginella species exhibit heterospory, producing two types of spores: microspores and megaspores, which develop into male and female gametophytes, respectively.
4. They play a vital role in their ecosystems by helping prevent soil erosion and contributing to the biodiversity of moist habitats.
5. Selaginella has been used in traditional medicine and is being researched for its potential in various biotechnological applications.

Review Questions

• Explain how the life cycle of Selaginella differs from that of flowering plants.
  • The life cycle of Selaginella involves alternating generations between the sporophyte and gametophyte phases. Unlike flowering plants that primarily reproduce through seeds produced in flowers, Selaginella reproduces through spores. The sporophyte generation produces spores, while the gametophyte generation is independent and produces gametes. This two-phase life cycle highlights the differences in reproductive strategies between seedless vascular plants like Selaginella and flowering plants.
• Discuss the ecological significance of Selaginella in its native environments.
  • Selaginella plays an important ecological role in its habitats by helping to stabilize soil and prevent erosion due to its ground cover. These plants thrive in moist environments, contributing to the biodiversity of forest floors and other shaded areas. Additionally, their ability to survive periods of drought by entering a dormant state allows them to persist in changing environmental conditions. This resilience supports ecosystem stability and provides habitat for various organisms.
• Evaluate the importance of studying Selaginella in understanding plant evolution and adaptation mechanisms.
  • Studying Selaginella provides critical insights into plant evolution, particularly regarding the transition from simple non-vascular plants to more complex vascular plants. Their unique characteristics, such as heterospory and desiccation tolerance, offer clues about how early land plants adapted to terrestrial environments. By examining Selaginella's genetic and physiological traits, researchers can uncover evolutionary strategies that have allowed plants to thrive in diverse habitats, informing both ecology and conservation efforts.

Related terms

Sporophyte: The diploid phase of the plant life cycle that produces spores through meiosis, which develop into the gametophyte generation.

Gametophyte: The haploid phase of the plant life cycle that produces gametes (sperm and eggs) through mitosis, leading to fertilization and the formation of a new sporophyte.

Vascular Plants: Plants that have specialized tissues (xylem and phloem) for conducting water, nutrients, and photosynthates throughout the plant, allowing them to grow larger and live in diverse environments.