ae eas ARE 
LEITNERIA FLORIDANA. 89 
Plate 87. — Tangential section of stem wood, above, showing dilated 
ray going to branch, 125; and, below, partial radial section of stem, 
60, the xylem at the left, the phloem at the right,—showing complete 
duct perforations, stratification of liber, and serial arrangement of crys- 
tal cells in the latter. 
Plate 38.— Cross section through wood and pith of stem, showing loca- 
tion of secretion passages, X60; and radial section of pith, showing the 
greater transverse diameter of its cells, x 125. 
Plate 39. — Cross section above, of outer part of wood and inner part 
of cortex, showing vernal row of ducts, quadrate liber, and, in the 
primary cortex, the small ducts of a foliar bundle; below, for compari- 
son, a corresponding section of Tilia Americana, with quadrate bast 
wedges,— both 60. 
Plate 40.— Cross section of primary cortex of very young stem, show- 
ing epidermis and collenchyma; below, cross section of liber wedge, 
showing thin walled bast fibers with secondary rays and transverse paren- 
chyma bands (the section torn through the cambium), — both 125. 
Plate 41. — Cross section of central portion of root, showing pith and 
xylem, — the large openings are ducts; below, longitudinal section of 
secretion passage in petiole, showing elongated form of secreting cells,— 
both 60. 
Plate 42. — 1, Enlarged radial section of stem xylem, showing medul- 
lary ray below, libriform cells at the right, striated transition to tra- 
cheides adjoining these, and striated tracheides with bordered pits at the 
upper left; 2, radial section, showing reticulated marking of medullary 
ray cells in contact with duct, 400; 3, enlarged longitudinal section of 
duct, showing bordered pits and remnant of original transverse septum ; 
4, much enlarged cross section of wood, showing secondary thickening of 
libriform and medullary ray cells; 5, diagram of radial section of xylem 
crossed by medullary ray, X200; 6, cross section, and 7, radial section 
of xylem, in diagram, 200, showing parenchyma layer at annual ring,— 
the vernal wood at the right, the autumnal growth atthe left; 8, diagram 
of tangential section of wood, showing libriform cells and medullary 
rays, 200. 
Plate 43.— 1, Radial section of xylem, showing libriform at the right, 
followed by tracheides, vessels, and wood parenchyma, the vessels sub- 
scalariform where adjoining a medullary ray, X200; 2, cross section of 
secretion passage in pith sheath, 320, pith at the left, xylem at the 
right; 3, radial section through the left hand portion of same, 200, be- 
ginning with pith at the left, and ending with the secreting cells at the 
right; 4, cross section of outer part of pith (above) with stellate crys- 
tals, pith sheath, and innermost part of a xylem wedge, showing two 
spiral ducts, 200; 5, radial section of outer cortex of old stem, show- 
ing stratified cork, 200; 6, similar enlarged section of stem toward end 
of first season, showing phellogen layer and subjacent collenchyma; 7, 
tangential section of subepidermal collenchyma of young stem, 200; 8, 
cross section, and 9, radial section of secondary bast, showing open bast 
fibers and interjacent bands of bast parenchyma, 200. 
25 
