1901] ERIOCAULON DECANGULARE 27 
Eriocaulon, seems more suitable than ‘‘stereomatic’’; moreover, 
it appears that it attains a still further development in other 
genera of the order, where it sometimes resembles true collen- 
chyma much more than in our species. 
The second form of mechanical tissue in the scape so much 
resembles stereome in its structure that it may be considered as 
stereomatic, but not as stereome proper. This tissue is but 
sparingly developed, and occurs only in one or two strata cover- 
ing the leptome of the bundles within the collenchymatic ribs, 
and as a few cells on the hadrome side of these same bundles. 
The lumen of these stereomatic cells is much narrower than in 
any portion of the collenchyma; moreover, the cells are longer 
and the cross walls are almost oblique. In no instance, however, 
did I observe this stereomatic tissue form a sheath around the 
mestome bundles; it seems to be restricted to a few strata on 
either face, separated from one another by the large vessels on 
the sides of the bundles. The small mestome bundles which 
are located within the chlorophyll bearing cortex are destitute 
of such stereomatic support. It would thus appear as if the 
mestome bundles are merely surrounded by continuous strata of 
collenchyma which only differs from that in the ridges in being 
less thick walled; and there is no indication of such structural 
peculiarities as might lead to a separation of it into two tissues, 
as a collenchymatic and an endodermal. The cells showed 
exactly the same shape and size all around the central cylinder, 
and in no place were the spots of Caspary, or any special 
arrangement usually noticeable in an endodermis, observed. 
However, when the sections were placed in concentrated sulfuric 
acid, a true endodermis became at once plainly visible. The 
collenchyma was rapidly destroyed, while a continuous ring of 
a single stratum of cells persisted for some time surrounding 
the mestome bundles and bordering on the leptome, but sepa- 
rated from it by the few strata of stereomatic tissue. The scape 
thus possesses an endodermis of the same structure as that 
observed in the rhizome. 
It has been stated already that the mestome bundles occur 
