36o 
L. H. MACDANIELS 
Parenchyma of two types: one narrow, divided-cambiform type heavily pitted 
on radial wall; the other large, thin-walled cells of conducting type, but nearly 
empty or containing crystals; both types in tangential bands. 
Three-year stem, three-year root. Sieve tubes in small groups between large fan- 
shaped rays; small, few, of same type as mature. 
Parenchyma of two types as in mature. 
One-year root. Sieve tubes not found ; cambiform and storage parenchyma abundant. 
Two-year twig. Sieve tubes about the same size and type as in three-year seedling; 
more numerous in twig. 
Eleagnus angustijolia 
Mature growing (fig. 20), Sieve tubes of type 3 with somewhat inclined sieve plates; 
lattice much as in Ulmus. 
Companion cells very abundant in corners of sieve tubes. 
Parenchyma of short, broad, divided-cambiform type; thin-walled. 
Cornus paniculata 
Mature root (figs. 37, 38). Sieve tubes small, slender; usually with a single trans- 
verse sieve plate; sometimes with 2-4 plates upon an oblique end wall; 
lattice a fine network enclosing pores much as in Acer. 
Companion cells present but not abundant. 
Parenchyma of divided-cambiform type with conspicuous sieve-like pitting on 
radial and terminal walls. 
Nyssa sylvatica 
Mature. Sieve tubes very long with oblique end walls; type 1 with 4-15 plates; 
plates in many cases present over entire radial wall where in contact with 
another sieve tube; frequently separated rather widely; lattice a very faint 
network with distinct pores in the meshes. 
Companion cells present but not abundant. 
Parenchyma scattered among sieve tubes; short divided-cambiform, full of 
protoplasm; abundant pitting on radial walls. 
Twig. Sieve tubes present with transverse sieve plates for most part; very thin- 
walled, resembling parenchyma cells but with easily recognized sieve plates. 
Parenchyma of very elongate, divided-cambiform type. 
Fraxinus americana 
Mature. Sieve tubes about the same shape as cambium cells; type 2 with 3-6 
plates; pores large; thin-walled; lattice not well developed. 
Companion cells abundant in corners of sieve tubes. 
Parenchyma of broad, divided-cambiform type; abundant, scattered among sieve 
tubes; very heavily pitted on radial walls. 
Two-year stem, two-year root, fast growth. Sieve tubes small, few, thin-walled, 
with single poorly developed transverse sieve plates; lattice not observed. 
Parenchyma as in six-year stem. 
One-year twig. Sieve tubes small, thin-walled, resemble parenchyma. Much like 
two-year seedling. 
