Hornwort
Description
Hornworts are small, non-vascular plants which belong to the division Anthocerotophyta, and is known as a Bryophyte. They are one of the oldest land plant lineages around, dating back roughly 500 millions years ago. Hornworts are named for their horn-shaped sporophyte structures, and unique for their green, flat-bodied structures (thallus), during the gamete phase.
Characteristics
Habitat
Hornworts are found in many ecosystems around the world. They are most abundant in moist environments such as forests, wetlands, and along stream banks. However, some species can tolerate dry conditions such as deserts or tundras.
Life Cycle
The life cycle of hornworts follows an alternation of generations between haploid and diploid phases:
- Hornworts have been used in traditional medicine for their medicinal properties
- They also have ecological significance, contributing to soil formation and nutrient cycling.
- In scientific research, hornworts are used as model organisms to research many properties of plant biology, and evolution.
Classification and Phylogeny
Hornworts belong to the division Anthocerotophyta, which is one of the three divisions of non-vascular land plants. They are further classified into various families and genera based on their morphological and molecular characteristics. There are currently about 200 known species, and there are constantly new discoveries, as this particular plant is understudied
Evolution
Hornworts are theorized to be one of the earliest groups of evolved land plants. They are suggested to have descended from algae species, roughly 500 million years ago. They have characteristics that suggest they evolved in primitive conditions, such as the lack of vascular tissues. Understanding the evolution of hornworts has played a significant role in the understanding of the colonization of land by plants. It is suggested that this is an early predecessor of vascular land plants, and branched off very early in the evolution of plants.
Uses
Terminology
Gametophyte: The haploid, gamete-producing phase in the life cycle of hornworts.
Sporophyte: The diploid, spore-producing phase in the life cycle of hornworts.