280 de Fraine . — The Morphology and Anatomy of the 
A 7 arrow - leaved 
S. binervosa = A. 
S. bellidifolia ~ B. 
? Hybrid, broad-leaved 
S. binervosa = c. 
Stem : 
(14 ») 
(27) 
(14 c) 
Type 
Short and subterranean 
Short and subterranean 
Short and subterranean 
Periderm 
Wide 
Wider than a 
Wide 
Cortex 
Not aeiating 
Slightly aerating 
Not aerating 
Sclerenchyma and 
sclereides 
Very abundant 
Very few 
Abundant 
Phloem 
Narrow zone 
Wide zone 
Narrow zone 
Medullary rays 
Narrow 
Wide 
Narrow 
Xylem : 
( Fibres 
Numerous 
Numerous 
Numerous 
J Primary vessels 
0*006 mm. in diameter 
0*006 mm. in diameter 
0.008 mm. in diameter 
I Secondary vessels 
o*oi 6 mm. in diameter 
0*020 mm. in diameter 
0*020 mm. in diameter 
Pith 
Many sclereides 
Few sclereides 
Intermediate between 
A and B 
Leaf'. 
Type 
Isobilateral (19 a) 
Bifacial (19 e) 
Bifacial (15 n) 
Thickness 
Thin. Average = 0*448 mm. 
Thicker than C 
Intermediate between 
A and B. Average 
= 0*^64 mm. 
Sclereides in blade 
Abundant (k a) 
Absent (r5 f) 
Few (15 f.) 
Sclerenchyma 
Much 
Little 
Intermediate between 
A and B 
Margin 
Long and narrow (20 a) 
Short and broad (20 c) 
lake a, but thicker 
(20 b) 
Cuticle : 
(21 B, B 1) 
Thick, ridged, plugs be- 
(21 H, H 1) 
Thick, less ridged, no 
(21 G, G 1) 
Thick, ridged, plugs 
( External 
tween the cells 
plugs 
present 
l Internal 
Present 
Traces only. 
Epidermal cells smaller 
than in A and c 
Present 
Glands : 
1 Mucilage 
Abundant 
Less abundant 
Abundant 
•1 Mettenian 
Uppersurface,6*2 persq.mm 
9*6 
8*3 
1 
Lower ,, 8-9 „ ,, 
8*3 
9*6 
Stomata 
Upper surface, 33*2 per 
sq. mm. 
73 M 
40* r 
Lower surface, 26*3 per 
sq. mm. 
35*9 
35 * 2 
I'etiole : 
Type 
Flat (i6j\) 
Channelled (16 d) 
Flat (16 b) 
Sclerenchyma 
Abundant 
Little 
Less abundant than in A 
Sclereides 
Numerous 
Absent, except in the 
Less numerous than 
sheath 
in A 
Inflorescence axis : 
Surface 
Smooth 
Very granulated (24 a, 
b ; 25 B) 
Two layers (23 c) 
Slightly granulated 
(23, A) 
Palisade layer 
One layer (23 a) 
Two layers (23 B) 
(The numbers and letters in round brackets indicate the diagram illustrating the character in question.) 
V. Summary. 
i. The morphology and anatomy of the forms of binervosa and 
*S. bellidifolia which occur at Blakeney Point, Norfolk, is described. 
Three main forms of binervosa are distinguished : 
(a) The tall form which grows on the edge of shingle fans on the 
Main bank (pp. 241 and 244). 
