prothallusn.

Brit.

/prəʊˈθaləs/, U.S.

/proʊˈθæləs/

Inflections: Plural prothalli.

Origin: Formed within English, by derivation. Etymons: pro- prefix², thallus n.

Etymology: < pro- prefix² + thallus n. Compare slightly earlier proembryo n.The derivatives prothallic adj. and prothalline adj. could instead be interpreted as being < prothallium n.

Botany.

1. The gametophyte of a pteridophyte (fern, horsetail, clubmoss, etc.), which is typically a tiny, free-living, thallus-like structure, produced by germination of a spore and bearing the sexual organs from which the sporophyte is produced. Also: a homologous structure in certain other plants, as the protonema of a moss (now rare) or the gametophyte, esp. the female gametophyte, of a gymnosperm.

ΘΚΠ

the world > plants > part of plant > reproductive part(s) > spore or sporule > cryptogam or plant having spores > [noun] > parts of > thallus

thallus1829

proembryo1854

prothallus1854

protonema1857

prothallium1858

thallome1875

blastema1880

prothallus1921

1854 J. H. Balfour in Encycl. Brit. V. 144/1 Equisetaceæ... The spore when sprouting, produces a pro-embryo or pro-thallus, which at first appears as a green-lobed leaf supported on a stalk.

1919 J. N. Martin Bot. for Agric. Students xvii. 432 The gametophyte is called a prothallus, the term referring to the fact that it is thallus-like in form and precedes the sporophyte in reproduction.

1931 J. A. Thomson in W. Rose Outl. Mod. Knowl. 212 An ordinary asexual Fern-plant produces spores which develop into minute sexual prothalli.

1965 K. R. Sporne Morphol. Gymnosperms i. 19 Cell-walls are being laid down between the nuclei of the female prothallus.

1992 Univ. Oxf. Bot. Garden News Autumn 7 Some species are heterosporous and in these cases the prothalli are dioecious.

2003 Daily Tel. (Nexis) 6 Sept. 6 Eventually, all being well, the prothallus develops both male and female parts on its underside.

2. An area of exclusively fungal tissue around the margin of a crustose lichen; a hypothallus.

ΘΚΠ

the world > plants > part of plant > reproductive part(s) > spore or sporule > cryptogam or plant having spores > [noun] > parts of > thallus

thallus1829

proembryo1854

prothallus1854

protonema1857

prothallium1858

thallome1875

blastema1880

prothallus1921

1921 Bryologist 24 72 Pannaria was also found..growing on tree trunks in shady ravines. Its interesting prothallus,..of the appe[a]rance of a thick felt-like black nap, is sure to attract attention.

1967 M. E. Hale Biol. Lichens i. 10 In many species there is a clearly defined black non-lichenized prothallus..which precedes the margin of the lichenized thallus.

2003 Lichenologist 35 120/2 Buellia tesserata is characterized by its greyish white..crustose thallus, clearly delimited by a dark, fimbriate prothallus.

Derivatives

proˈthallic adj. rare = prothallial adj.

ΚΠ

1890 Cent. Dict. Prothallic, of or relating to the prothallium.

1901 Bot. Gaz. 31 348 The second and third [fronds] bore prothalli, even profusely, on their surfaces, a sort of prothallic rash as it were.

1992 Botanica Acta 105 449 Other less organized prothallic structures..are also described.

† prothalline adj. Obsolete = prothallial adj.

ΘΚΠ

the world > plants > part of plant > reproductive part(s) > spore or sporule > cryptogam or plant having spores > [adjective] > of or having parts > of or having thallus

thalline1856

thalloid1857

thallodic1860

prothalline1868

thallodal1871

prothalloid1874

protonemal1875

prothallial1876

thalliform1891

protonematal1900

thalloidal1900

thallose1900

1868 Amer. Naturalist 2 520 Filaments..which have issued from other nourishing cells on the same prothalline scale.

1894 Bull. Torrey Bot. Club 21 178 The delicate prothalline tissue.

This entry has been updated (OED Third Edition, September 2007; most recently modified version published online March 2022).

单词	prothallus
释义	prothallusn. Brit. /prəʊˈθaləs/, U.S. /proʊˈθæləs/ Inflections: Plural prothalli. Origin: Formed within English, by derivation. Etymons: pro- prefix², thallus n. Etymology: < pro- prefix² + thallus n. Compare slightly earlier proembryo n.The derivatives prothallic adj. and prothalline adj. could instead be interpreted as being < prothallium n. Botany. 1. The gametophyte of a pteridophyte (fern, horsetail, clubmoss, etc.), which is typically a tiny, free-living, thallus-like structure, produced by germination of a spore and bearing the sexual organs from which the sporophyte is produced. Also: a homologous structure in certain other plants, as the protonema of a moss (now rare) or the gametophyte, esp. the female gametophyte, of a gymnosperm. ΘΚΠ the world > plants > part of plant > reproductive part(s) > spore or sporule > cryptogam or plant having spores > [noun] > parts of > thallus thallus1829 proembryo1854 prothallus1854 protonema1857 prothallium1858 thallome1875 blastema1880 prothallus1921 1854 J. H. Balfour in Encycl. Brit. V. 144/1 Equisetaceæ... The spore when sprouting, produces a pro-embryo or pro-thallus, which at first appears as a green-lobed leaf supported on a stalk. 1919 J. N. Martin Bot. for Agric. Students xvii. 432 The gametophyte is called a prothallus, the term referring to the fact that it is thallus-like in form and precedes the sporophyte in reproduction. 1931 J. A. Thomson in W. Rose Outl. Mod. Knowl. 212 An ordinary asexual Fern-plant produces spores which develop into minute sexual prothalli. 1965 K. R. Sporne Morphol. Gymnosperms i. 19 Cell-walls are being laid down between the nuclei of the female prothallus. 1992 Univ. Oxf. Bot. Garden News Autumn 7 Some species are heterosporous and in these cases the prothalli are dioecious. 2003 Daily Tel. (Nexis) 6 Sept. 6 Eventually, all being well, the prothallus develops both male and female parts on its underside. 2. An area of exclusively fungal tissue around the margin of a crustose lichen; a hypothallus. ΘΚΠ the world > plants > part of plant > reproductive part(s) > spore or sporule > cryptogam or plant having spores > [noun] > parts of > thallus thallus1829 proembryo1854 prothallus1854 protonema1857 prothallium1858 thallome1875 blastema1880 prothallus1921 1921 Bryologist 24 72 Pannaria was also found..growing on tree trunks in shady ravines. Its interesting prothallus,..of the appe[a]rance of a thick felt-like black nap, is sure to attract attention. 1967 M. E. Hale Biol. Lichens i. 10 In many species there is a clearly defined black non-lichenized prothallus..which precedes the margin of the lichenized thallus. 2003 Lichenologist 35 120/2 Buellia tesserata is characterized by its greyish white..crustose thallus, clearly delimited by a dark, fimbriate prothallus. Derivatives proˈthallic adj. rare = prothallial adj. ΚΠ 1890 Cent. Dict. Prothallic, of or relating to the prothallium. 1901 Bot. Gaz. 31 348 The second and third [fronds] bore prothalli, even profusely, on their surfaces, a sort of prothallic rash as it were. 1992 Botanica Acta 105 449 Other less organized prothallic structures..are also described. † prothalline adj. Obsolete = prothallial adj. ΘΚΠ the world > plants > part of plant > reproductive part(s) > spore or sporule > cryptogam or plant having spores > [adjective] > of or having parts > of or having thallus thalline1856 thalloid1857 thallodic1860 prothalline1868 thallodal1871 prothalloid1874 protonemal1875 prothallial1876 thalliform1891 protonematal1900 thalloidal1900 thallose1900 1868 Amer. Naturalist 2 520 Filaments..which have issued from other nourishing cells on the same prothalline scale. 1894 Bull. Torrey Bot. Club 21 178 The delicate prothalline tissue. This entry has been updated (OED Third Edition, September 2007; most recently modified version published online March 2022). < n.1854
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