210 THE Lire History or 
PLATE 29 
Fic. 101. Surface view of thizome, with the leaves removed to show the two- 
ranked arrangement, and the two primary bundles, at. 
Fic. 102 Diagram of leaf bundles : a, bundle of rhizome; 4, the two primary 
bundles ; c, first lateral bundle ; d, second lateral bundle. 
FiG. 103. Nine diagrams showing different cross sections of leaves with bundles. 
the lateral bundles have been given off; 9 shows the apex of a leaf with one lateral 
bundle ending free, 
Fic. 104. Diagram of middle portion of leaf: a, central bund] posed of p 
of the two primary bundles ; 6, thick-walled cells surrounding bundle ; c, mesophyll 
4, band of thick-walled cells and epidermis ; €, groove (under side of leaf) ; /, lateral 
bundle; c, denser mesophyll of upper side of leaf. XE. 
arta 
Fics. 1 ross sections of petioles showing different degrees of ی‎ 
of the outer parenchymatous cells of the cortex. Fig. 105 is more often found in : 
Sporophylls. 1, upper Side; a, primary bundles, In Fig. 106 one lateral bundle is 
shown, 4, X 25. : 
‘Fic. 107. Cross section of centra] bundle of leaf; a, phloém; 4, xylem ; e, endo- 
dermis; q, thick-walled cells of the ground tissue surrounding bundle. 
Fic. 108. Cross section of one of the lateral bundles. Marking as in Fig ge 
f, mesophyll of under side; f thin-walled epidermal layer which gives rise to 
sporangia. X 120, ; ; 
Fic. 109. Curled apex of young sporophyll showing scales, a, and cut so as to y 
the bundles, ۸۰ and ۱۳۳ ۲0۳9 6. W te. 
Fic. 110, Side view of apex of young leaf showing curl and glands. X 13. 
Fic. ۰ Front view of same, 3 
Fic. 112, Portion of epidermis from under side of young leaf; a, scale; 4, gland; 
€, stoma just forming, X.. ۱ 
PLATE 30 
Fic. 113. Apex of leaf. Dotted line indicates the area of the dense mesophyll - 
cells, containing chlorophyll, under epidermis. X 87, 
IG. 114. Portion of upper side of leaf, Over bundle, seen in cross section ; $ 
epidermis; 4, thick-walled cells, generally Prosenchymatic, often becoming bast-like+ 
^ mesophyll cells containing chlorophy], X 87. 
Fic. 115, Portion of epidermi 
stoma, d. Marking as in Fig, 114. 
Fic. 116. Rid 
S, 4, from under side of young frond showing i 
Sê over bundle on under side, مد‎ 87. in 
- Inner mars; e ; 4 3 rking as 
Nie vis X 8. rgin of groove extending from ridge to ridge. Ma : | 
سب‎ ML folding of the epidermal walls. Fig. 119 has um 
Mn with potash to show the Way they fit into each other. — 
^ 120, of surface of under side of leaf showing the ridge and 
grooves, a, the stomata and glands, X 13. 
Fic. 121. Epidermis from groove; q, stoma ; 4, gland. X87. 
