80 FIRST FORMS OF VEGETATION. 
LYCOPODS OR CLUB-MOSSES. 
There is a class of plants whose external 
appearance and mode of growth would indicate 
that they belong to the tribe under review, but 
whose structure and functions are so different, 
that they are commonly supposed to bear a 
closer analogy to the ferns. They occupy an 
intermediate position, and form a connecting link 
between ferns and mosses; I allude to the 
Lycopods or club-mosses. They are usually 
found in bleak, bare, exposed situations in all 
parts of the world, and sometimes attain a large 
size ; forsaking the creeping habit peculiar to the 
family, and becoming slightly arborescent in 
tropical countries, particularly New Zealand, rival- 
ling in rank luxuriance the smaller shrubs of the 
forest. The British representatives of the class 
are comparatively small plants, with the exception, 
perhaps, of the commonest species (Lycopodium 
clavatum, Fig. 4), which creeps along the ground 
among the heather on the moorlands, and sends 
out runners or creeping stems in all directions to 
the length of several yards, which take a firm 
hold of the soil by means of long, tough, wiry 
roots on their under-surface. The smallest species 
is the marsh club-moss (Lycopodium inundatum), 
