prothallus

[ proh-thal-uhs ]

noun

, Botany.

, plural pro·thal·li [proh-, thal, -ahy].

1. prothallium.

prothallus

/ prəʊˈθælɪəm; prəʊˈθæləs /

noun

1. botany the small flat free-living gametophyte that bears the reproductive organs of ferns, horsetails, and club mosses. It is either a green disc on the soil surface or it is colourless and subterranean

prothallus

/ prō-thăl′əs /

, Plural prothalli prō-thăl′ī

1. The gametophyte of homosporous ferns and some other plants. Prothalli have chlorophyll for photosynthesis, but they are not differentiated into roots, stems, or leaves. They are usually small, flat, and delicate. Prothalli develop from germinated spores, and they bear both archegonia for producing eggs and antheridia for producing sperm.
2. See more at alternation of generations

Derived Forms

• proˈthallic, adjective

Word History and Origins

Origin of prothallus¹

From New Latin, dating back to 1850–55; pro- ², thallus

Word History and Origins

Origin of prothallus¹

C19: from New Latin, from pro- before + Greek thallus a young shoot

Example Sentences

With L. inundatum, however, the prothallus is green and leaf-like.

From Project Gutenberg

It is obviously important that the male and the female prothallus should be together.

From Project Gutenberg

Malic acid has, however, been discovered to be present in the prothallus as a whole.

From Project Gutenberg

Prothallus, the leaf-shaped green organism that grows from the spore of a fern and produces sexual organs, 49.

From Project Gutenberg

Prothallus green, formed upon the ground, often variously lobed, usually dicious.

From Project Gutenberg