Exostome


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Ex´o`stome


n.1.(Bot.) The small aperture or foremen in the outer coat of the ovule of a plant.
References in periodicals archive ?
(2001), the genus Cryphaea can be identified by its erect habit, lateral sporophytes, ovoid almost sessile capsules, and papillose exostome teeth.
Peristome well developed; exostome yellowish, brownish towards base, lower outside ornamentation cross-striolate, upper outside ornamentation papillose, border broad, widened where ornamentation changes from cross-striolate to papillose; endostome hyaline to yellowish, basal membrane high, about 35-40% of endostome height, segments perforated, papillose, cilia 2-3, long, appendiculate at least in upper part of cilia, otherwise nodose.
Peristome well developed; exostome yellowish, lower outside ornamentation dotted (reticulate at high magnification), upper outside ornamentation papillose, border broad; endostome hyaline to yellowish, basal membrane high, 40-45% of endostome height, segments narrowly perforated, papillose, strongly papillose in upper part, cilia 2-3, long, nodose.