516 HUTCHINSON'S POPULAR BOTANY 



appearance. There is usually a rigid wiry stem which forks repeatedly, and 

 is covered with overlapping small undivided leaves, which either invest the 

 stem all round or are arranged in from two to six rows. Some exotic 

 species have erect stems, and of these certain tropical ones are stout arid 

 shrubby. Several have even become climbers, and a few have given up 

 their connection with the earth and grow only upon trees (epiphytic}. 

 The kidney-shaped sporange is attached by a short stout foot-stalk to the 

 base of the upper side of the sporophyll or leaf. It is one-celled, and 



Photo by] IE. Step. 



FIG. 658. MARSH CLUB Moss (Lycopodium inundatum). 



This species is leas noticeable than the others, from its habit of keeping close to the soil in marshy places, and 



from the shortness of its stems which die back in winter. The fertile branches are erect and end in slightly 



thickened cones, which are evident in summer. 



splits when ripe into two valves. The numerous spores are more or less 

 rounded, marked with three radiating lines on the upper side, and on 

 germinating, the exospore splits along these lines into three valves, from 

 which the endospore projects and grows into the germinating filament. A 

 transverse wall (septum) develops across the filament and divides it into 

 a small basal cell and a larger apical cell. No further change occurs in 

 the basal cell, but the apical one divides into two series of cells, and 

 each of these cells afterwards divides into two. Each cell is provided with 

 a few grains of chlorophyll, except in Lycopodium annotinum, whose 



