1900] OBSERVATIONS ON LESSONIA 333 
PLATE XX, 
Fig. 1. Diagram of end of branch bearing two pairs of leaves, the outer 
pair without midribs and bearing sori, the inner with midribs and without sori. - 
Fig. 2. Cross section of haptere showing epidermis, superficial cambium, 
and ground tissue. : 
Fic. 3. Longitudinal section of haptere through superficial area. 
Fic. 4. Longitudinal section through central portion of haptere showing 
elongated parenchymatous cells. 
1G. 5. Section through older area of holdfast showing irregular and dis- 
torted structure due to appression and coalescence of original haptere 
ranches, 
Fic. 6. Diagram of cross section through stipe 12° above holdfast show- 
ing flat pith and zones of secondary thickening. 
Fig. 7. Cross section through outer cortical area of stipe 1% in diameter 
tg epidermis, cambial tissue, chlorenchyma, and transition to scleren- 
chyma, . 
Fig. 8. Cross section through zone of secondary thickening showing por- 
tion of a “ray’’ caused by the section striking the middle of adjacent cells in 
atadial row ; between two of the cells button-shaped masses of cell-wall sub- 
Stance have been developed. 
Fig. 9. Section through same area as last showing two “rays ee 
slightly different levels so that the shapes of the component cells are differ- 
ent: the majority of the cells have been cut across their arms giving a 
sclerenchymatous appearance. ts 
Fic. Io. Cross section through the zone of tissue nearest to the 
wing the absence of arms and consequently of “ rays,”’ and illustrating the 
a sclerenchymatous appearance of this region. : 
: u, Cross section through the pith of same stipe showing the 
ne web of hyphz with cells packed with reserve materials. : 
i. fais Longitudinal section through outer cortex and epidermis ; transi- 
armed to outer cells. 
pith 
PLATE AX, 
13. Longitudinal section through secondary growth zone of stipe 
ement side by 
Fic, 
maintained by the 
dinary sclerenchy- 
“ rays” as in 
= i . re 
armed oN Diagrammatic representation of the position 
Matous “"S) Cross sections at point a would show the or 
Ag. 9 “tucture, while those made at point 4 would show the 
a wing on the left 
Fig, cS 
ay a Longitudinal section of stipe near the pith s a 
© the pith web, and on the right the sclerenchymatous cells 
in 
ner Stowth zone, : 
