180 



T. Holm — Studies in the Cyperacece. 



thickened. Stereome is present and forms isolated bundles on 

 the lower surface, one near the midrib, and two on each side, a 

 short distance from the margins. 



The prophyllon 

 of the spikelet shows a very simple structure, there being no 

 mestome but merely about five ribs of stereome, two of which 

 are larger than the others so as to render the leaf bicarinate. 

 Epidermis is developed on both faces excepting near the mar- 

 gins, where it becomes reduced to one single layer. The epi- 

 dermal cells are very thin-walled, and none are developed as 

 bulliform cells. 



The bract 



of the flower shows nearly the same structure as that of the 

 spikelet, but much thinner (fig. 6). The epidermis is reduced 



Fig 6. Transverse section of a floral bract of L. maculata, showing the mid- 

 rib and half of the blade ; cells containing tannin are drawn with black, x 320. 



to a single layer in the lateral parts, from the midrib to the 

 margins, while the margins themselves possess a double epi- 

 dermis. Stereome is present, but only on the dorsal face of 

 the scale covered by epidermis, and tannin-reservoirs were 

 observed in some of the epidermal cells, indicated with black 

 in the accompanying figure (fig. 6). 



TJie pericarp 

 consists of three distinct layers : an outer epidermis of very 

 thin-walled cells, each containing a silicious cone with minute 



warty surface, a few strata of scle- 

 reids, and finally an inner epi- 

 dermis. The cells of the iuner 

 epidermis are very thin-walled and 

 show a rectangular outline in trans- 

 verse sections (fig. 7). A skeleton 

 of silica is readily obtained by the 

 usual preparation, and shows that 

 not only the cones are silicified, 

 but also a part of the epidermis 



Fig. 7. Transverse section of 

 the pericarp of L. maculata. Ep = 



the outer epidermis; Scl. = the a b ove t ] iese (fi™ g an( j g\ 

 layers of sclereids ; ep. = the mi ±. ^ 



layers of sclereids ; ep. 

 inner epidermis, x 560. 



The roots are very slender and 

 show a rather open structure. 



