T. Holm — Studies in the Cyperacece. 21 



reservoirs, which might be of some use to these plants in the 

 dry seasons. A different view has, meanwhile, been expressed 

 by Seignette, who (1. c. p. 39) describes the structure of Avena 

 elatior var. bulbosa {A. bulbosa Willd.), and who found a large 

 quantity of starch deposited in the fundamental tissue. 



The stem above-ground. 



It is cylindric, but furrowed in F. scirjpoidea, and, as already 

 stated, consists of numerous internodes. The epidermis-cells 

 are relatively small, perfectly smooth, and stomata are, of 

 course, well represented in this tissue. The bark-parenchyma 

 shows a very characteristic palissade-tissue of several layers, 

 and is interrupted by large groups of stereome. The inner 

 part of the bark passes gradually over into a colorless tissue, 

 which occupies the interior part of the stem ; the mestome- 

 bundles are arranged in a band and are to be observed in the 

 green bark, just inside the groups of stereome, which border 

 on their colorless parenchyma-sheaths. A very few mestome- 

 bundles are, also, noticed in the fundamental tissue, and these 

 show a much larger lacune in the hadrome-part than is to be 

 observed in the bundles of the outer band. The stem of F. 

 squarrosa shows a somewhat different structure ; it is terete, 

 furrowed and smooth, but much weaker than that of the pre- 

 ceding species. The cells of epidermis are large and very 

 thin-walled, and the green bark consists only of about seven 

 strata, in which lacunes are to be observed. The mestome- 

 bundles are arranged in two alternating bands and located in 

 the very large, colorless- parenchyma, which occupies the cen- 

 tral-cylinder ; the bundles are supported by large groups of 

 stereome, which reach through the green bark to the epidermis 

 itself. Characteristic of the stem of this species is the pres- 

 ence of lacunes, one between each of the two mestome-bundles 

 and several in the fundamental tissue, rendering the stem 

 almost hollow. 



The leaf 



of F. scirpoidea has a long, tubular sheath but only a minute, 

 rudimentary blade. A transverse section of the blade (fig. 17) 

 is thick, but very narrow. The epidermis consists of rather 

 large cells, but none of them are, however, developed as 

 " bulliform," although some of the cells above the midrib are 

 considerably larger than the others ; stomata (fig. 18) are espe- 

 cially abundant on the inferior face of the small leaf-blade as 

 well as on the sheath. These stomata are not prominent, but 

 almost in niveau with the surrounding cells. The mesophyll 

 (the black tissue in fig. 17) consists of rather closely-packed 



