Holm, Soaie uew anatomical characters for certain Gramineae. Il5 



of these ; it is less developed in the other species, but shows the 

 same distribution, besides that it occurs also beneath the furrows 

 in 0. canadensis and asperifoUa. In regard to the mesophyll, 

 this tissiie is only developed in 0. micrantha as palisades through- 

 out the blade, and those that border on the mestome-bundles 

 radiate towards the center of these ; in the other species this tissue 

 consists mostly of much shorter, almost roundish cells, which, 

 however, become somewhat stretched, where they approach the 

 nerves, and attain there a form and position corresponding to 

 those, which we observed in 0. micrantha. 



A green , thin-walled parenchyma - sheath surrounds each 

 mestome-bundle, and the cells are quite narrow, when viewed in 

 transverse section. In cases where the stereome borders on the 

 parenchyma-sheath, the cells of this sheath show then a thicke- 

 ning, as we noticed also in Süpa; but in no instance did we 

 observe an Interruption, caused by the adjoining stereome. A 

 mestome-sheath with the inner cell-walls thickened is also to be 

 found in these species, and is continuous in the large as in the 

 small mestome-bundles ; moreover one or a few strata of thick- 

 walled mestome-parenchyma may be observed in the larger bundles 

 between the leptome and hadrome. 



The mestome-bundles are all located in the ribs, none in the 

 furrows. They are mostly oval (in transverse section) in 0. melano- 

 carpa and asperifoUa, or nearly all orbicular in the two other 

 species. 



Eriocoma Nutt. 



Eriocoma cuspidata Nutt. from the plains of Colorado possesses 

 a narrow, conduplicate leaf- blade, the structure of which cor- 

 responds almost exactly to that of Oryzopsis micrantha^ especially 

 as to the deep, narrow furrows on the ventral face, the strougly 

 developed mechanical tissue and the mesophyll, being represented 

 by distinct palisades vertical on the leaf- blade or radiating towards 

 the center of the mestome-bundles. The parenchyma-and mestome- 

 sheaths show the same structure observed in Oryzopsis, but the 

 mestome bundles, which are mostly orbicular are not in Eriocoma 

 confined to the projecting ribs, but occur also in the furrows 

 beneath the small bulliform cells. 



The stereome and the mestome-sheath of Eriocoma appear to 

 be relatively more thick-walled and porous than we observed in 

 any of the species of Oryzopsis, even in 0. micrantha^ besides 

 that the outer cell-wall of epidermis is very heavily thickened on 

 the dorsal face of the leaf in this genus. 



Nassella Desv. 



N. trichotoma Hackel, from the mountains of Uruguay, has a 

 very narrow and conduplicate leaf-blade, of which the dorsal face is 

 not only protected by a heavily thickened epidermis, but also by 

 a continuous mass of stereome, which Covers the entire face until 

 the margins in several broad layers. The ventral face of the 

 blade is deeply furrowed and the thin-walled epidermis is on the 



