T. Holm — Studies in the Cyperacece. 9 



shape or arrangement of proper bulliform cells. The meso- 

 phyll forms throughout a compact tissue, containing much 

 chlorophyll and is differentiated as a palissade tissue on the 

 upper face of the blade. Tannin-reservoirs are not uncommon 

 in the mesophyll. Mestome-bundles of two degrees of devel- 

 opment separate the mesophyll, which shows a distinct constric- 

 tion at each bundle, as shown in the accompanying figure 2. 

 A usual colorless parenchyma-sheath and a rather thin-walled 

 mestome-sheath surround the bundles, the larger of which are 

 supported by stereome on both faces, above and below. The 

 smaller mestome-bundles show only a few stereome-cells on 

 their leptotne-side. 



The same distribution of bulliform cells as representing only 

 one group above the midrib is also met with in other species of 

 Scleria, and appears to be the commonest arrangement. We 

 have observed it in 8. triglomerata, 8. oligantha, 8. ciliata, 8. 

 filiformis, 8. Elliottii, 8. Baldwini and 8. reticularis. But 

 in none of these species does the leaf-blade show the deep fur- 

 rows which we observed in 8. pauciflora, and which gives the 

 section the peculiar constricted appearance. The epidermis- 

 cells of the upper face are, however, also very large in these 

 species, increasing in size towards one of the largest of the 

 lateral ribs, but without becoming specialized as proper bulli- 

 form cells. It is, furthermore, characteristic of these species 

 that one or two of the lateral ribs project very strongly on the 

 upper face, while in S. pauciflora they were all situated below 

 the surface, in shallow furrows. Stomata occur on both faces 

 of the blade in these species, in contrast to 8. pauciflora. Some, 

 but slight, variations were also noticed in the thickness of the 

 cell-walls of epidermis and stereome ; we observed, for instance, 

 a very thick-walled epidermis in 8. ciliata, 8. Baldwini, & 

 filiformis, and 8. Elliottii / a thick-walled stereome in 8. cili- 

 ata and 8. Baldwini, besides that the mestome-sheath showed 

 a more prominent thickening in these two species than in any of 

 the others. 8. reticularis is the only species in which the stereome 

 on the upper face of the leaf -blade is separated by mesophyll from 

 the mestome-bundles. Characteristic of the remaining three 

 species : 8. Torreyana, 8. hirtella and 8. verticillata is the 

 presence of more than one group of bulliform cells, there being 

 three between the larger lateral ribs in 8. Torreyana besides 

 the one above the midrib. In the two other species the epi- 

 dermis between each two mestome-bundles and above the mid- 

 rib is developed as bulliform cells, the number of groups 

 corresponding to the width of the leaves, about four on each 

 side of the keel of 8. verticillata, eight or nine in 8. hirtella. 

 The other tissues, the mesophyll, with reservoirs of tannin, 

 the stereome and the mestome-bundles show much the same 



