ALG AS 
99 
posed of multitudes of spherical cells, each cell representing 
a complete Glwocapsa body. One of the peculiarities of the 
plant is that the outer part of the cell 
wall becomes mucilaginous, swells, 
and forms a jelly-like sheath. Among 
the cells examined there will be found 
some that are dividing, a wall extend- 
ing across the spherical cell and di- 
viding it into hemispheres. Each 
hemisphere is a new plant which 
Fic. 93.—A, Nostoc: showing the chain-like fila- 
ment and a heterocyst (a); B, Gleotrichia: 
showing mucilage sheath, basal heterocyst, 
and tapering apex. 
Fia.92.—Gleocapsa: show- 
ing single cells, and small 
groups that have been 
formed by division and 
are held together by the 
enveloping mucilage. 
grows as large as the 
parent cell and then 
divides in turn. The 
mucilaginous walls hold 
the cells together, and 
so they are found in 
groups of various sizes 
(Fig.92). Thismethod 
of reproduction by cell- 
division is the simplest 
kind of reproduction. 
59. Nostoc.—These 
plants occur in jelly- 
like masses in damp 
places. If the jelly be 
examined, it will be 
found to contain em- 
bedded in it numerous 
