bitegmic

bitegmic

[bī′teg·mik]
(botany)
Having two integuments, especially in reference to ovules.
References in periodicals archive ?
Both species have bitegmic and anatropous ovule, obturator, trichomes and a resinuous gland, which is composed of flange-like structures that are modified bractlets (Webster and Webster, 1972).
alata are anatropous, subglobose, bitegmic, and crassinucellate, with a narrow conical nucellus (see Figure 4D, E).
mollissma were anatropous bitegmic and crassinucellate.
mollissima was the same as those reported for other species of in terms of the anatropous bitegmic and crassinucellate ovules and the Polygonum type embryo sac (Xu et al.
He further pointed out that the remaining significant morphological difference--number of ovule integuments--putatively justifying a separation between Itea (bitegmic) and Choristylis (previously reported as unitegmic) is based on a misinterpretation of the number of ovule integuments in Choristylis (Kubitzki, 2007a).
(2011) consider Hylocereus ovules as amphitropous, bitegmic and crassinucellate, which during mega-gametogenesis and embryogenesis show abnormalities, suggesting apomixes.
The seed of the genus Capparis is bitegmic. The testa is 0.2-0.3 mm thick, with all its cell walls somewhat lignified, some of them with distinct thickening; its tegmen consists of an outer fibrous, lignified layer four to ten-cell thick, with a lignified endotegmen composed of contiguous cuboid cells, with strongly thickened radial walls.
Microdiptera (in the broadest sense) is morphologically and anatomically similar to Decodon, sharing the following characteristics: anatropous ovules, bitegmic seeds with inner lignified layers typical of the Lythraceae, a germination valve on one side of the seed, and extensive spongy tissue through which the raphe runs from near the hilum to the chalaza.
The ovary is monocarpellate and the mature ovule is anatropous, bitegmic and crassinucellate.
Ovule: (0) orthotropous, bitegmic; (1) anatropous or hemianatropous, bitegmic; (2) anatropous, unitegmic (Davis, 1966; Palkovic, 1974; Orchard, 1975; Corner, 1976; Cronquist, 1981; Dahlgren & Thorne, 1984; Webb & Gornall, 1989; Kubitzki, 1993b).
Furthermore, most tenuinucellate dicotyledons are also unitegmic, as Dablgren (1975) noted, whereas the majority of "primitive" dicotyledons and monocotyledons have bitegmic ovules (Endress, 1990, 1994; Dahlgren & Clifford, 1982).