What is a liverwort and how many species exist?
Liverworts are non-vascular land plants forming the division Marchantiophyta. Scientists estimate there are about 9,000 species, and at least 85 percent of them belong to the leafy group.
Questions about Liverwort
Short answers, pulled from the story.
How do liverworts differ from mosses?
The most reliable distinction is that liverwort rhizoids are single-celled while moss rhizoids are multicellular. Liverworts also uniquely contain membrane-bound oil bodies filled with isoprenoids, a feature found in no other plant. Thallose liverworts have a flat body plan never seen in mosses, and leafy liverworts often have deeply lobed leaves arranged in three ranks.
How old are liverworts according to the fossil record?
Fossilised liverwort spores found in Argentina in 2010 date to the Middle Ordovician, around 470 million years ago. Compression fossils of Pallaviciniites from the Upper Devonian of New York are also among the earliest specimens assigned to the group.
How do liverworts reproduce?
Liverworts reproduce both sexually and asexually. Sexual reproduction requires water, as the biflagellate sperm must swim to reach the egg; researchers have recorded liverworts firing sperm-containing water up to 15 centimetres through the air. Asexual reproduction occurs through structures such as gemmae, which in Marchantia polymorpha can be scattered up to 120 centimetres by rain splashing into their cups.
Why are liverworts called liverworts?
The name comes from an Old English term meaning liver plant. In ancient times it was believed liverworts could cure liver diseases, a belief grounded in the Doctrine of Signatures, which held that a plant's appearance indicated its medicinal use.
What is the economic importance of liverworts?
Direct economic use is limited; Riccia fluitans is sold for aquarium use as a floating habitat for invertebrates and fish. Indirectly, liverworts reduce streambank erosion, retain water in tropical forests, and form protective soil crusts in deserts and polar regions. Marchantia polymorpha is also a significant greenhouse weed.