protonema

[ proh-tuh-nee-muh ]

noun

, Botany.

, plural pro·to·ne·ma·ta [proh-t, uh, -, nee, -m, uh, -t, uh].

1. a primary, usually filamentous structure produced by the germination of the spore in mosses and certain related plants, and from which the leafy plant which bears the sexual organs arises as a lateral or terminal shoot.

protonema

/ ˌprəʊtəˈniːmətəl; -ˈnɛmətəl; ˌprəʊtəˈniːmə /

noun

1. a branched threadlike structure that grows from a moss spore and eventually develops into the moss plant

protonema

/ prō′tə-nē′mə /

, Plural protonemata prō′tə-nē′mə-tə,-nĕm′ə-

1. The green filamentous or flat, thallus-like structure that grows from the germinated spores of liverworts and mosses and eventually gives rise to a mature gametophyte.

Derived Forms

• ˌprotoˈnemal, adjective

Other Words From

• proto·nemal adjective

Word History and Origins

Origin of protonema¹

1855–60; < New Latin < Greek prōto- proto- + nêma thread

Word History and Origins

Origin of protonema¹

C19: from New Latin, from proto- + Greek nema thread

Example Sentences

Erect branches may arise from the protonema, and gemmae may be developed on it.

From Project Gutenberg

In mosses (fig. 12) a filamentous growth, the protonema, is first formed, and the leafy plants arise upon this.

From Project Gutenberg

Usually the protonema is filamentous and ceases to be evident after the plants have developed.

From Project Gutenberg

The protonema forms a flat, lobed, thalloid structure attached to the soil by rhizoids, and the plants arise from marginal cells.

From Project Gutenberg

The spore on germination forms a short filament which soon broadens out into the thalloid protonema.

From Project Gutenberg