ATTN MEA CHCA KTM CTC ccactre 
sp ’ 
\ 
Fia. 16.—The various chief elements of the wood of the 
oak, isolated by maceration, and highly magnified. f,a 
fibre, distinguished by its thick walls, simple slit-like 
pits, and no contents; w.p, part of a row of wood-paren- 
chyma cells, with simple pits, and containing starch in 
winter; ¢7, a tracheid, distinguished from the fibre 
especially by its bordered pits; p.v, part of a rather large 
pitted vessel, made up of communicating segments, each 
of which corresponds to atracheid, and bas bordered pits 
on its walls; sy, part of a spiral vessel. 
