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1. The outermost layer of the wall of certain spores.
2. An asexual spore developed externally by budding, as from a sporophore.


(Botany) the outer layer of the spores of some algae and fungi
ˌexoˈsporous adj


(ˈɛk səˌspɔr, -ˌspoʊr)

the outer coat of a spore.
ex`o•spor′ous, adj.
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References in periodicals archive ?
Sporoderm is 4 [micro]m thick, formed by perispore and exospore. Perispore is microrugulate with rugulae homogenously distributed; it is adhered to exospore in young spores but tends to detach; detaching usually begins at the laesure zone in mature spores.
Micromorphology of outer exospore coatings in Selaginella megaspore.
l'exospore chez les Pteridophytes (ultrastructural data of the
Mature spores have a dense exospore coat, a pale endospore, and single rows of 8-11 polar tubule coils (Figure 2, panels B, C).
The spores ranged from 1.4 to 2.4 urn in length and were characterized by an outer electron-dense exospore and a thick electron-lucent endospore.
Braun, the pattern is similar, but the term "outer exospore" is used instead of "paraexospore" (Uehara et al., 1991).
These changes are: #20, quadriseriate branching of axes/leaves absent [right arrow] throughout; #28, stele with radiating arms of xylem absent [right arrow] as rounded lobes; #41, radial axis/rachis trace round-elliptical [right arrow] lobed; #46, position of protoxylem in rachis/axis toward no face [right arrow] toward several faces; and #88, exospore surface nearly smooth or plain [right arrow] obviously sculptured.
[57] found that exospores secreted by MSCs similarly reduced myocardial schema/reperfusion (I/R) injury in mice.
68 of length 9: Aserinsky (family name, OED), ater-miner, afternoons, aucthores, avengings, axenfelds (eye problem), brimmings, bucklings, bydweller, Cogglesby (proper noun, OED savage), crepillit, cwelleras, Dominguez (personal name), drillings, drinkings, duellings, duffields (type of cloth, OED half-thick), dweller by, dwellings, dwillings, exospores (OSPD), frillings, fumositez (c 1400 q, OED original), grillings, grimoires, grip-knobs, Posht-e Waz (Afghanistan) 8 of length 10: ascriptive, aucthorite, aucthorize, by-drinking, Emi Klingue (Libya)
Whittenbury R, Davies SL, Davey JF (1970) Exospores and cysts formed by methane utilising bacteria.