Thallus

Thallus (pl.: thalli), from

organs.^[1] Many of these organisms were previously known as the thallophytes, a polyphyletic

group of distantly related organisms. An organism or structure resembling a thallus is called thalloid, thallodal, thalliform, thalline, or thallose.

Even though thalli do not have organized and distinct parts (

analogous structures that resemble their vascular "equivalents". The analogous structures have similar function or macroscopic structure, but different microscopic structure; for example, no thallus has vascular tissue. In exceptional cases such as the Lemnoideae

, where the structure of a vascular plant is in fact thallus-like, it is referred to as having a thalloid structure, or sometimes as a thalloid.

Although a thallus is largely undifferentiated in terms of its anatomy, there can be visible differences and functional differences. A kelp, for example, may have its thallus divided into three regions. The parts of a kelp thallus include the holdfast (anchor), stipe (supports the blades) and the blades (for photosynthesis).^[2]

The thallus of a fungus is usually called a mycelium. The term thallus is also commonly used to refer to the vegetative body of a lichen. In seaweed, thallus is sometimes also called 'frond'.

The

horsetails, and ferns is termed "prothallus

".

References

^ Haupt, Arthur W. (1953). Plant Morphology. New York: McGraw-Hill Book company. p. 7.
^ "The term thallus is a botanical term that refers to the body of a plant that does not have leaves". www.botany.hawaii.edu.

[1] Haupt, Arthur W. (1953). Plant Morphology. New York: McGraw-Hill Book company. p. 7.

[2] "The term thallus is a botanical term that refers to the body of a plant that does not have leaves". www.botany.hawaii.edu.

[1]

[2]

See also

References