306 T. Holm — Studies in the Cyperacece. 



a mere rudiment, we have felt inclined to consider these organs : 

 the cushion-like body in the Gramineoe and the tubular pro- 

 phyllon (P 1 ) in Gyperus, as probably being identical formations. 



That the bracts, corresponding with the involucral leaves 

 (B 1 ) in Cyperus. ma} T be observed in the Graminese, has been 

 mentioned by some European agrostologists, and they are 

 quite often developed to such extent that their sheath and 

 blade may be distinguished. In a number of species of Festuca, 

 Bvomus, Schedonorus, etc., these little bracts are very distinct, 

 at least at the lower secondary branches of the panicle, but they 

 are seldom free, i. e., the sheath and the apex is mostly adnate 

 to the subtended branch. However in Panicum proliferum 

 we have observed one instance where the lowermost bract was 

 provided with a free blade about 20 mm in length. The structure 

 of this little bract varies within the respective genera, and may 

 prove useful to the distinction of species, as shown by Lange 

 in Sched 'ononis. But in regard to the supposed clado-prophyllon 

 in the panicle of Gramineoe, we have not succeeded in detect- 

 ing any case where this was developed as an open or free leaf, 

 as are the prophylla of the vegetative branches in this same 

 family. However we have noticed some points in their structure 

 which tend to support our opinion about their real morpho- 

 logical identity, that they represent leaves: " fore-leaves." 



These organs are quite large in Zizania aquatica, and we 

 have seen one case, where one of these cushions was extended 

 into two free tips, simulating the bidentate apex of a pro- 

 phyllon. It is, furthermore, to be pointed out that in numerous 

 species, and of the most diverse genera, the external structure 

 of these bodies is like that of the leaf-sheaths : when the 

 stem-leaves, and particularly the sheaths, are hairy, the same 

 kind of hairy covering seems constantly to be observed in these 

 cushion-like organs, and when the sheaths are glabrous these 

 organs are, also, glabrous. Another point which we think 

 deserves notice is, that these same organs never surround the 

 branches, but are always, as stated above, located on the upper 

 face only of the respective branch. Their internal structure 

 suggests that which is characteristic of the fore-leaves in Cyperus, 

 since we observed a large mass of collenchymatic tissue, which 

 was not in direct continuation with the tissues of the rhachis 

 itself, but was distinctly separated from the peripheral circle of 

 mestome-bundles and their continuous layers of stereomatic 

 tissue. A series of consecutive sections taken from a secondary 

 branch revealed the fact, that the cushion-like body, even 

 if it be adnate to the rhachis, does not in any place consti- 

 tute a regularly developed tissue as a portion of the rhachis, 

 but that it represents something supplemental and of which 

 the presence does not influence the structure or arrangement 



