Perforation plates predominantly simple; variously scalariform
plates occasional (Fig.
barbourii (with <=20 bars) had scalariform
The particles presented hollow-spheroid-like shape and the surface micro-structure was scalariform
Resistances to fluid flow of model xylem vessels with simple and scalariform
74, 82-83) shorter than S10, with a ventro-basal triangular process directed anteriorly on inner margin; a distal area of differentiated scalariform
like cuticle (May, 2002) on mesal surface (as in Fig.
tracheids attached to Artisia (his Sternbergia) pith casts, Dawson assumed that at least some of these fossils must have belonged to Sigillaria, based on the common occurrence of scalariform
tissue in that plant (Dawson 1859).
Figure 7 shows the formation of gas bubbles at the scalariform
vessel walls of Vitis vinifera.
The pits are present in opposite or scalariform
The seed coats are moderately or deeply reticulate with layers of scalariform
thickenings on the radial walls.
Bailey & Tupper (1918) offered a muchreproduced drawing schematizing the tracheid as a primitive type of tracheary element in angiosperms; from this, vessels (first with scalariform
, ultimately simple perforation plates) were progressively derived on the one hand, whereas on the other hand, imperforate tracheary elements progressively lost pit borders and changed (by implication, gradually) from conductive to mechanical cells.
6 whorls, which regularly increasing in size, and are strongly shouldered and scalariform
Protoxylem tracheids, 6-12 [micro]m in diameter, are characterised by annular and spiral thickening with scalariform
and transitional pitting seen on the 9-15 [micro]m diameter metaxylem tracheids (Fig.