166 BOTANICAL GAZETTE [MARCH 
cell. The tissue systems described by HANSTEEN are present and 
each seems to have the function ascribed to it, although without 
_rigidity. . Each system, too, has its origin in the group of segments 
surrounding the apical cell and can be traced very near it. The cells 
of every system are meristematic in the apical region, but the epider- 
mal cells are apparently the only ones which retain this activity. 
The cells of any one of the three systems correspond well in general 
appearance with the similarly placed cells described by HANSTEEN, 
but an interesting modification was observed in the cells of the con- 
ducting system. All are long and of small diameter, but in respect 
to thickness of walls the tissue is differentiated into two regions. The 
inner cells have thin walls, while the outer ones have thick walls. The 
thick-walled cells may be both supporting and conducting in func- 
tion. The conducting system of a leaf blade consists only of thin- 
walled tissue. No intercellular filaments, as reported by REINKE, 
have beenfound. Sometimes, however, a filamentous alga creeps into 
the mucilaginous walls of cells near the surface of a leaf or old stem, 
and gives the appearance of intercellular filaments. As the little alga 
contains true starch, its cells when stained with iodin present a 
sharp contrast to the unstained cells of Sargassum. HANSTEEN 
_ (792) figures pores in thin areas consisting of the middle lamella in 
Sargassum baccijerum, and REINKE (’76) represents similar areas 
but without pores in cell walls of Fucus vesiculosus. Such thin areas 
are common between cells in the tissues of Sargassum filipendula, 
but pores, though probably present, are rarely seen. 
The character of the reserve material in Sargassum proved of great 
interest. Sections from plants which have been preserved in forma- 
lin contain much more stored material than tissues which have been 
kept in alcohol. Preparations, however, which have passed through 
alcohol, xylol, paraffin, the heat of the bath, etc., still contain within 
the cells of the epidermis and outer cortex, many bodies which in all 
probability represent reserve food material. These’ bodies, which 
stain readily, vary in size and structure, but are evidently related, for 
transitional stages can be found between the most extreme forms. 
Judging by the appearance of the structures,some are intact and others 
modified. Those which seem intact are spherical, with a diameter 
which equals or exceeds the length of a chromatophore. Each con- 
