Genus S/a/ice as represented at Btakeney Point. /. 279 
practically the only difference between the two lies in the greater develop- 
ment of air-spaces in bellidifolia and the greater width of the cork layer. 
The distribution of tannin is similar in the species to that of 
5 . binervosa. 
3. The Leaf (cf. p. 249). 
The general structure of the leaf is shown in Text-fig. 15, F ; it is dis- 
tinctly fleshier than in any of the forms of S. binervosa , and is at once 
distinguished from them by the absence of sclereides in the blade and 
petiole, though they occur in the leaf sheath ; sclerenchyma fibres are also 
very few in number, and are present only as a small cap above and below 
the main veins. The details of the leaf and petiole structure are shown in 
Text-figs. 15 D, 19 E, 20 C, 21 H, and 21 H 1 ; they have been described 
on pp. 266-73 in comparison with the leaves of S. binervosa . 
4. The Inflorescence Axis (cf. p. 25c). 
The general structure of the inflorescence axis resembles that of 
5 . binervosa (see pp. 273-6), but the number of bundles in the inner ring 
is usually much fewer. As in binervosa , frequent anastomoses take place 
between the small cortical strands and also between the bundles of the 
inner and outer ring. The main bundles of the scale leaves are furnished 
from one of the inner ring of bundles, and the remaining bundles are 
provided by the cortical strands. Details of the structure of the axis are 
given on pp. 273-6, and are illustrated in Text-figs. 23 C, 24 A and B, 
and 25 B. 
IV. Comparison of the Anatomy of the Broad-leaved 
S. BINERVOSA AND ITS POSSIBLE PARENTS. 
Narrow-leaved 
S. binervosa — A. 
S. bellidifolia = B. 
? Hybrid , broad-leaved 
S. binervosa — C. 
Root : 
Type 
Periderm 
Cortex 
Sclerenchyma and 
sclereides 
Phloem 
(12 A : 10) 
Shingle 
Present 
Not aerating 
Abundant 
Very narrow zone 
(26) 
Marsh 
Wider zone than A 
Aerating 
Absent throughout the 
greater length of root 
Wide zone 
Shingle 
Present 
Not aerating 
Less abundant than 
in A 
Intermediate between 
A and B 
Xylem: 
' Fibres 
Wood parenchyma 
1 Primary vessels 
k Secondary vessels 
Numerous 
Absent 
| o*oio mm. diameter 
1 0*020 mm. diameter 
Few 
Abundant 
0*006 mm. diameter 
0*028 mm. diameter 
Numerous 
Absent 
0*012 mm. diameter 
0*032 mm. diameter 
U 
2 
