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Related to prothallus: sorus, indusium, homosporous


 (prō-thăl′əs) or pro·thal·li·um (-thăl′ē-əm)
n. pl. pro·thal·li (-thăl′ī) or pro·thal·li·a (-thăl′ē-ə)
A small, flat, delicate structure produced by a germinating spore and bearing sex organs. It is the gametophyte of ferns and some other plants.

[New Latin : pro- + Greek thallos, shoot (from thallein, to sprout).]

pro·thal′li·al (-lē-əl) adj.


(prəʊˈθæləs) or


n, pl -li (-laɪ) or -lia (-lɪə)
(Botany) 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
[C19: from New Latin, from pro- before + Greek thallos a young shoot]
proˈthallic, proˈthallial adj


(proʊˈθæl i əm)

n., pl. -thal•li•a (-ˈθæl i ə)
the gametophyte of ferns and related plants.
[1855–60; < Greek pro- pro-2 + thallíon, diminutive of thallós young shoot; see -ium2]
pro•thal′li•al, pro•thal′lic, pro•thal′line (-ˈθæl in, -aɪn) adj.
pro•thal′loid, adj.
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References in periodicals archive ?
Thallus corticolous, up to 2 cm diam, continuous, white-grey with a silvery shine, minutely uneven-verrucose; prothallus not observed.
danaeifolium, the prothallial plate expands laterally by the increased activity of some of the lateral intercalary cells of the ribbon thallus, and develops into a broad spatulate plate in which a meristem is differentiated on the side facing the posterior end of the prothallus, contrary to the condition in A.
There were differences between both stations for this species in term of its morphological features moreover on its thallus colour and prothallus textures.
The sporangia within each sorus produce spores that germinate and develop into a prothallus, which grows into a heart-shaped gametophyte.
cotyledon damping off direct-seeding emergence etiolation [F.sub.1] hybrid geotropism harden-off hybrid imbibe imbibition mycorrhizae open-pollination pasteurization prothallus radicle scarification sorus (sori) stratification viability
Thallus evident, areolate to subsquamulose; prothallus lacking 3 2.
These palynomorphs are characterized by openings or scars (apertures) through which the pollen tube and prothallus emerged.
Gravity does not appear to have an independent effect on the later events of prothallus and secondary rhizoid growth in the gametophyte, for the growth of prothallial cells follows the same direction as that of the first prothallial cell, and the growth of secondary rhizoids follows the same direction as that of the primary rhizoid, no matter how the gametophyte is oriented.