154 IOWA ACADEMY OF SCIENCES. 



other specie?. The cuticle (c) and cell wall, are well developed in 

 this species. The leaf is strongly involute on the upper sur- 

 face and here we also find papillae. 



The bulliform cells (b) are also much larger than in the 

 other species, there being four to six in a row, sometimes one 

 large central cell and sometimes two large central cells with two 

 smaller bulliform cells on either side of the large ones. 



The carene (c), in this species consists of five mestome 

 bundles (m), three very small, a large central, and one medium 

 in size. The leptome (1) and hadrome (h) are fully developed in 

 the two" large bundles. The hadrome is separated from the 

 leptome by two layers of thick walled parenchyma. One small 

 mestome bundle occurs on each side of the medium bundle. 



The mestome bundles are all connected with each other by 

 the mesophyll (m). 



The mestome bundles number thirty- eight, eighteen on 

 left and twenty on right side of carene (c). In this species three 

 types of bundles occur: First, those open on both sides; 

 second, those open above only; and third, those entirely closed. 

 Those of the third type are of two sizes one very small, the 

 other somewhat larger. The mestome bundles of the third 

 type predominate. The sides of the leaf terminate with a 

 closed bundle. In the mestome bundle of the second type the 

 leptome and hadrome seem to be in immediate contact with 

 each other, but in those of the first type they are separated 

 by thick-walled parenchyma. The chlorophyll bearing paren- 

 chyma does not differ materially from that found in other 

 species. 



The stereome (st) is on the lower side of all the bundles and on 

 the upper side of those of the first and second type. The leaf 

 also terminates with irregular groups of stereome. The ste- 

 reome is quite well developed in the carene where it occurs- 

 in large groups. 



The mesophyll (mes) in this species connects the different 

 mestome bundles and consists of both round and elongated 

 cells. 



The uncolored parenchyma is more strongly developed in 

 this than in any of the other species of Sporobolus studied. It is 

 prominent in the midrib, where it occupies the space above the 

 five mestome bundles. It also occurs immediately below the 

 bulliform cells and on the upper side of the mestome bundles. 



