Marchantia polymorpha

Common Liverwort is a primitive, moss-like plant that forms leaf-like mats on the soil surface. It is a member of the thalloid liverwort family, a group of nonvascular, strap-like, green plants that often forms large colonies on the surfaces on which it grows. The Common Liverwort does not have phloem and xylem like ferns, conifers and flowering plants to transport water, food and minerals through the plant. The plant body, or thallus, is not differentiated into stems, roots, and leaves. Numerous rhizoids attach the thallus to the soil. As a result, liverworts tend to be small, a few cells thick, and grow in moist locations.

Common Liverwort reproduces by wind-dispersed spores and (more commonly) by gemmae produced in cup-like structures. Gemmae are splashed out of the cups by rain or irrigation. Liverworts prefer moist, cool conditions, and occur primarily in crops with frequent irrigation, such as propagation areas and herbaceous perennials. It does not require natural light to grow and has been shown to reproduce under artificial light.

Common Liverwort can be very challenging to manage. Inspect plants before purchase and eradicate new infestations of Liverwort before it can spread. Liverworts have been suppressed by some pre-emergence herbicides, mulches, and non-selective contact herbicides.  Persistent infestations will require frequent hand weeding and changes in cultural practices to achieve acceptable suppression.

Common Liverwort is among the largest species of Marchantia and is often used in biology labs. If it is present in container plants, it may repel water, causing the pots to dry.