exosporium


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ex·o·spo·ri·um

(ek'sō-spō'rē-ŭm),
The outer envelope of a spore.
References in periodicals archive ?
a) the average ascospore volume in tetrasporic asci: 15,000 um3 instead of 10,000 um3 and 5,000 um3, the last two measured in the single last two Tuber species, respectively; b) the ascospores shape and ornamentation: spherical (22.5-55 um), rarely sub-spherical, enclosed by a reticulate-alveolate exosporium with net meshes delimited by 4-6 walls 5-7.5 um high; c) a peridium constituted by very small and flat warts, almost never transversely striated; d) the odour, at first phenolic (3-methylanisole), then grateful due to the presence of ethyl-methyl-chetone, without any phenolic component; e) thecolour of the gleba, light-brown with numerous, irregularly flexuous and subtle sterile veins; f) theovoid (77-95 x 7-115 um) asci, supported by a hooked pedicle and containing 1-6 spores.
Ascospores were mostly ellipsoid or ovoid in mature asci of both species.The exosporium reticulum was rather regular in T.