T. Holm — Studies in the Oyperacew. 439 



(1) the relatively broad and flat, as we find it in F. autumnalis, 

 F. thermalis, F spadicea, F. puberula, F. complanata and 

 F. laxa ; (2) the semi-cylindrical in F. castanea and (3) the 

 approximately triangular in the remaining species. Yery 

 characteristic of the leaves of the first category is the more or 

 less, but always very conspicuous, asymmetric blade, in contradis- 

 tinction to those of the other species, a fact that has, also, 

 been recorded by Rikli as common to F. glomerata (Nees) and 

 F. paupercula (Bklr.) In F. autumnalis the leaf, as will be 

 seen from the accompanying illustration (fig. 1), is flat and 

 strictly dorsi ventral ; only the midrib is somewhat projecting 

 on the lower surface of the blade, and this is due to its larger 

 support of stereome. The upper face is perfectly smooth, 



Fig. 1. Transverse section of half of the leaf-blade of F. autumnalis. x 75. 



and there is nothing in the outline to indicate the peculiar 

 position of the blade, as we have mentioned already, being 

 placed edgewise by the twisting of the leaf-sheath. This form 

 of leaf must not be confounded with the sword-shaped leaves 

 of Iridacew, because both faces are equally well developed in 

 Fimbristylis autumnalis, besides in F. complanata. 



The leaf is more likely to be compared with that of a mature 

 Fucalyptus or of our evergreen species of Smilax, of which 

 the leaves show a similar position. It is strange to see that 

 such peculiar leaf-position is said to be either " a xerophytic 

 character of bog-plants or a natural adaptation of desert- plants." 

 However in these species of Fimbristylis the leaf-blade is 

 developed with this position immediately after germination, 

 and we have not noticed any exceptions to this rule in speci- 

 mens from less dry situations, nor in plants growing in 

 Sphagnum-moss. It is a character that seems to be peculiar to 

 these two species, but which cannot possibly be considered as 

 having originated through any means of adaptation, since the 

 structure is identical with that of the other species, in which 

 the ventral leaf-face is turned towards the stem. 



While the epidermis of the upper face in F. autumnalis 

 consists only of one layer of large, thin-walled cells of equal 

 width all through the blade, we find in F. complanata several 

 layers, representing a typical water-storing tissue. Among the 



