


- eee ee ee i : 
1901] ERIOCAULON DECANGULARE 25 
When the mestome bundles break through the endodermis 
to the cortical parenchyma, they appear much smaller and are 
then surrounded by a thin-walled endodermis, showing the same 
power of resisting concentrated sulfuric acid as does the main 
endodermis. They are almost regularly arranged in two con- 
centric bands, and are either strictly collateral or more or less 
bicollateral, in the same manner as those of the fundamental 
tissue. The general structure of the rhizome, therefore, does 
not differ from that of other monocotyledonous plants, with the 
exception of the development of the epidermis into long hairs, 
which is known in a very few other orders. The mestome 
bundles of Eriocaulon being collateral or more or less com- 
pletely perihadromatic do not differ from those of rhizomes of 
most of the other monocotyledonous orders. Attention may be 
called, however, to a very peculiar structure which Poulsen dis- 
covered in the rhizome and stem of Actinocephalus polyanthus 
Kth. (Eriocaulacee), and which may be found in some of the 
other genera. The mestome bundles exhibit a form very 
unusual among the phanerogams, in being perileptomatic in 
the cortex and exohadromatic in the fundamental tissue; in the 
latter the perihadromatic bundles are surrounded by a tissue 
Which is suggestive of leptome, and around this again is a band 
of vessels, each mestome bundle consisting thus of a central 
Stroup of leptome surrounded by two bands of hadrome sepa- 
rated from each other by a band of apparently leptomatic tissue. 
THE SCAPE. 
The inflorescence, a capitulum, is borne at the apex of a long, 
slender, solid and twisted scape, which is distinctly furrowed 
and consists of only one internode with a single leaf, the long 
tubular sheath of which surrounds the scape to about its middle. 
In a transverse section of the free part of the scape, there is 
shown an epidermis of roundish cells, covered by a thin, smooth 
Cuticle. The size of the cells varies somewhat, and the largest 
are observable in the furrows, where they cover the green cor- 
tex. Stomata and hairs are present and exhibit the same 
