106 THE JOURNAL OF BOTANY 
The seeds are equally characteristic; thus :— 
Seeds polished . . . Pe P.O eae 
Seeds rough. 
Testa irregularly pitied . . . . . - - WN. marina, 
Testa regularly pitted. 
Pits much broader than lon N. minor. 
Pits fairly isodiametrical or slightly longer 
than broad . graminea. 
Appended is a brief dticnatic Wstiasis of our British species, 
ancient and modern 
Suscenvs I. cee agzas.—Dicecious. Plants of a sturdier habit 
than in Caulinia, with a greater iat differentiation of stem a 
leaf. Leaf-teeth aa inck of leaf and internodes spiny. Male 
flower eaalouek ¢ na spathe, anther quadrilocular. Female flower 
aire oe with three styles. Testa of more than three hardened 
cell-layers 
1. N. marina L. Sp. Pl. 1015 (1753) ; Arthur Bennett in Journ. 
Bot. 1883, 35 358, t. 241; Reid, Origin of British Flora, 159 (1899) ; 
Rendle in Trans. Linn. Soe. ser. 2, v. 889, t. 39, figs. 1-30 (1899). 
N. — Allioni, F). Pedem. ii. 221 (1785). 
Englan d.—Hickli ing and Martham Broads, Norfolk. Mr. Reid 
has found aie ts i pares at the following localities :—Barry 
‘he : 
eem to ng mmon ro form, characterized by 
sparsely spine-armed internodes, leaves 7-10 lines long, rarely 
ringette Li ith marginal oot not exceeding . es as 
It also occurs in India, China, Australia, North America (New 
York), and Jamaica. Its present more restricted area in Britain 
is Sine due to disappearance of suitable localities 
Suzcenus I]. Cavimia.—Monecious. Plants generally more 
delicate, with a less tissue-differentiation than in Eunajas ; leaves, 
except at the midrib, only two cell-layers thick ; $s teeriotlen un- 
armed; leaf-margin variously toothed, no dorsal s spines, 
Section 1. Americane.—Only the male flowers enclosed in a 
spathe. Leaf-sheaths sloping. Y eiodhce 8, all except N. flerilis 
co to America 
