IOWA ACADEMY OF SCIENCES. 153 



The chlorophyll bearing parenchyma can be divided into 

 two parts. First, large parenchyma cells surrounding the 

 bundles; these consist of rather large cells somewhat roundish 

 in shape; second, elongated cells in one or more rows around 

 the first. 



SPOROBULUS CRYPTANDRUS. 



The epidermal cells in this species do not differ from those 

 described for S. heterolepis. The bulliform cells (b) are some- 

 what larger than those in the first species, usually two or three 

 quite large cells and two smaller on each side. One or two 

 groups of bulliform cells occur between a large mestome 

 bundle, and, as in S. heterolepis, these do not occur between 

 the last two bundles. 



The carene (c l ) has one mestome bundle (m) which is open on 

 both sides. It is somewhat larger than other mestome bundles. 

 The leptome (1) and hadrome (h) are separated from each other 

 by thick- walled parenchyma (p 1 ); two rows of thick parenchyma 

 occur around the leptome. 



The mestome bundles are of three types: First, those open 

 above and below; second, those open above only, and third, 

 such as are entirely closed. Those of the third type are 

 more numerous than others. One mestome bundle is 

 entirely closed and at the side of the leaf, those of the third 

 type alternate with those of the second and first types. The 

 second type is more numerous than the first. Ten bundles 

 occur on each side of the carene. The mestome bundles of the 

 third type are usually found between two groups of bulliform 

 cells. The chlorophyll bearing parenchyma (c. b. p.) is about 

 as in S. heterolepis. The leptome in this species differs from 

 leptome in S. heterolepis in not being depressed on the upper 

 side. 



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

 and also upon the upper side of all bundles except those of the 

 third type. The cells of the sterome are not so thick walled as 

 in S. heterolepis. 



The mesophyll consists of elongated cells in one or two 

 rows around each mestome bundle. There seems to be mesophyll 

 connecting the bundles beneath the unclosed parenchyma. The 

 unclosed parenchyma is found in one or two rows around the 

 bulliform cells in contact with the mesophyll. 



SPOROBOLUS HOOKERI. 



The epidermal cells (e) of this species are small, thick 

 walled and uniform in size, they are more roundish than in 



