prothallium

[ proh-thal-ee-uhm ]

noun

, plural pro·thal·li·a [proh-, thal, -ee-, uh].

1. Botany. the gametophyte of ferns and related plants.
2. the analogous rudimentary gametophyte of seed-bearing plants.

Other Words From

• pro·thalli·al pro·thallic pro·thal·line [proh-, thal, -een, -ahyn], adjective
• pro·thalloid adjective

Word History and Origins

Origin of prothallium¹

1855–60; < New Latin < Greek pro- pro- ² + thallíon, diminutive of thallós young shoot; -ium

Example Sentences

The spore produces the small green prothallium by cell-division in the usual way, and this completes the cycle of fern life.

From Project Gutenberg

At a later period, other organs are found also on the back of the prothallium.

From Project Gutenberg

The prothallium is of a peculiar dull-green colour, different from that of the young frond which is subsequently formed.

From Project Gutenberg

To make these, the prothallium should be placed between small pieces of pith, and the razor must be very sharp.

From Project Gutenberg

As soon as the fern is firmly established, the prothallium withers away.

From Project Gutenberg