276 The Botanical Gazette. [October, 



groups of very thick-walled leptome-parenchyma are also 

 observable in the strongest bundles. The stereome, the 

 mesophyll and the uncolored parenchyma agree entirely with 

 that of U. Palmeri. The leaf structure of a series of specimens 

 of D. maritima, male and female, but from widely separated 

 localities is here compared : 



Arizona, ? : The stereome is rather weakly developed and 

 the blade is relatively broader. — California, $: Agrees in all 

 details with the specimen from western Texas, described 

 above. — New Jersey, ? : Especially characterized by the very 

 rough inferior face of the leaf, due to numerous warts. The 

 stereome is very strongly developed above and below the 

 mestome-bundles.- — Montana, 6 : Differs from all the above 

 mentioned female plants in having a closed ring of merely 

 thin-walled parenchyma inside the proper sheath, and no 

 thick-walled parenchyma either in the leptome or between this 

 and the hadrome. The superior epidermis shows very long 

 thorn-shaped and curved expansions. — Arizona, $ : The 

 superior epidermis shows short, thorn-shaped expansions, and 

 long hairs, especially towards the base of the blade, situated 

 among the bulliform cells. The inferior epidermis is on the 

 contrary nearly smooth and without any hairs. The mestome- 

 bundles show the same structure as described above for the 

 female specimen, and the groups of stereome are strongly 

 marked. — Washington, $ : Both faces of the leaf are very 

 rough, and the stereome shows an exceedingly strong develop- 

 ment. There is a closed ring of very thick-walled parenchyma 

 inside the proper sheath of the largest mestome-bundles, and 

 the leptome is nearly divided into two separate groups by 

 similar cells. — Vancouver Island, 6 : This specimen is well 

 characterized from the preceding in having merely a horse- 

 shoe-shaped layer of thick-walled parenchyma on the leptome 

 side. — Montana, $ (alkaline soil) : This specimen, compared 

 with that described above from the same locality, but not from 

 the same- kind of soil, shows a remarkable difference in having 

 a layer of very thick-walled parenchyma inside the proper 

 sheath. Groups of similar cells are scattered in the leptome 

 and a layer separating it from the hadrome. The superior 

 epidermis has warts, but no long thorns, and the inferior one 

 is nearly smooth with only a few projecting warts. 



t D. manUm**& t w . strict* $ from Nebraska: This 

 form is especially characterized anatomically by the hairv and 



