22 
FERNS AND FERNERIES. 
Though this tissue exists in the stem and other parts of 
the frond, it is better observed in transverse sections of 
the root of ferns, in which even the naked eye discerns 
rows of black dots, with intervals of a lighter colour (fig. 
12, a). The dots are bundles of cellular and ligneous 
(woody) tissue, the latter being the vascular tissue of the 
plant, which is almost entirely composed of scalariform 
vessels arranged in circular forms. So very characteristic 
are these vessels that the late Professor Queckett, from 
a small broken fragment of a funereal urn forwarded to 
him for examination, containing on its inner surface 
fibres of a brown colour, found after microscopial 
investigation that the fibres consisted almost entirely 
of scalariform vessels (fig. 12, b , c) precisely similar to 
those occurring in the Brake Fern ( Pteris ). This fern, 
he afterwards ascertained, is very abundant in the dis¬ 
trict in which the urn was discovered, and it is highly 
probable that portions of the fronds of the fern were 
placed in the urn before the ashes of the deceased per¬ 
son were deposited in it. 
The habitats of ferns are so various that it is almost 
impossible to give a complete list. The following species 
