This section grouped species with (a) carbonized stromata, (b) conical-papillate ostioles surrounded or not by a discoid area, (c) smooth ascospores usually with dehiscent perispore
but with a thickening of 1/3 of the length of the ascospores and (d) nodulisporium-like anamorphs.
Such pollen was first described by Brenner (1963) as two species of Peromonolites, a fossil-genus for monolete spores with a perispore
, but it was reinterpreted as monosulcate angiosperm pollen by Norris (1967), Doyle (1969), and Singh (1971).
La structure fine de l'exospore et de la perispore
des filicinees II.
triphylla were trilete, non-chlorophyllous, amber in colour, with slightly rugose perispore
, and nearly rounded in shape, with little variation in size, 32.9 [+ or -] 1.9 x 35.2 [+ or -] 2.4 [micro]m (Fig.
was smooth, with small papillae, or reticulate.
Sporoderm is 4 [micro]m thick, formed by perispore
morphology and the taxonomy of the Australian Aspleniaceae.
could be divided into three groups by their perispore
the middle and outer strata of the perispore
or elements on the outer
In Isoetes setacea Lam., the paraexospore (sensu Tryon & Lugardon, 1991) forms the outer layer of the microspore and is then covered by the perispore
. In I.
of meio/microspore: 0 = absent; 1 = thin, conforming to contours of exine; 2 = thick, forming contours of spore wall.
The plasmodium is enclosed by a membrane (the perispore
membrane; Tiwari & Gunning, 1986b) surrounding the tetrads or young free microspores as shown in Tradescantia, Anigozanthos, and Hypaxis [ILLUSTRATION FOR FIGURES 8, 15, 59 OMITTED].