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 (yo͝or′ĭ-dĭn′ē-əm) also u·re·di·um (yo͝o-rē′dē-əm)
n. pl. u·re·din·i·a (-dĭn′ē-ə) also u·re·di·a (-dē-ə)
A reddish pustulelike structure that is formed in the tissue of a plant infected by a rust fungus and produces urediniospores.

[New Latin ūrēdinium, from Latin ūrēdō, ūrēdin-, blight, from ūrere, to burn.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(ˌyʊər ɪˈdɪn i əm)

n., pl. -din•i•a (-ˈdɪn i ə)
the fruiting body of the rust fungi that bears urediospores.
[1905–10; < New Latin, = Latin ūrēdin-, s. of ūrēdō blight (see uredo)]
u`re•din′i•al, adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
References in periodicals archive ?
Once uredinia appear on the surface of wheat leaves, a large number of urediospores may be liberated after rupture of the uredinia and then be spread by air, which may result in secondary infections.
Uredinia abaxial, brown, rounded, scattered, 0.8-2 x 0.6-1 diameter.
The symptoms initially appear as small yellow pustules containing uredinia, which may cover large portions of the abaxial leaf surface.
Uredinia hypophyllous, yellowish, minute, covered with ruptured epidermis, pulverulent, scattered over the whole leaf surface, surrounded by numerous incurved paraphyses.
Beginning in July 2010, and annually since, symptoms of brown to black foliar spotting with margins of chlorosis and signs of abundant uredinia production were observed on plots of 3 year-old 'Alamo' and 9 year-old 'EG1101' switchgrass, established at the Leveck Animal Research Facility in Starkville, Mississippi (Figures.
Uredinia are observed initially in the dark dots that progressively acquire a light brown to red brown color and open in a minute pore releasing the colorless urediniospores, which become tan and accumulate around the pores (Balardin, 2002; Yorinori et al., 2004; Almeida et al., 2005).
The rating scale of infection responses in these evaluations consisted of four classes: R (resistant), MR (moderately resistant), MS (moderately susceptible), and S (susceptible) determined primarily on the basis of the size of uredinia. Based on natural field infection in Colorado, Hatcher is moderately resistant to stripe rust (caused by Puccinia striiformis Westend.; 4.3 score, 1 = resistant and 9 = susceptible, n = 4 evaluations).
Two different components of reproductive output corresponding to different stages of the pathogen's life cycle, formation of uredinia (pustules) on leaves and production of urediniospores by the uredinia, are modeled as functions of the strains' inoculum and uredinial densities, respectively.
Uredinia amphigenous, subepidermal, golden brown to blackish brown, present in rows, scattered but somewhat compact, naked, 0.06-0.11 x 0.094-2 mm.