124 Botanisches Centralblatt. — Beiheft 2. 



Dear Denver and Manitou, Colorado. It is the tallest of the 

 Gramineae of the plains and is strongly stoloniferous. — The 

 leaves are long, relatively broad and are equally furrowed on 

 both faces. A few, scattered, hairs occur on the upper face, 

 while the lower is nearly glabrous. There are small groups of 

 bulliform cells in the furrows on the upper face, which cover 

 narrow layers of colorless tissue between the ribs. The sto- 

 mata are almost level with the epidermis and occur on both faces 

 of the blade. 



A thick-walied stereome accompanies the mestome-bundles 

 and borders on the parenchymasheath on the leptome and the 

 hadrome-side of these. The mesophyll. which is thus confined to 

 the ribs, cousists of palisades, all of which are arranged radially 

 around the mestome-b.undles. These are surrounded by a large- 

 celled, thin-walled and green parenchyma-sheath, and also by a 

 moderately thickened mestome-sheath, which is continuous in all 

 the bundles. Several layers of thick-walled mestome-parenchyma 

 were observed around the leptome. The outline of the mestome- 

 bundles is always oval. 



Buchloe dactyloides Engelm., 



the famous „BufFalo-grass", covers large areas of the dry 

 plains in North America, and is frequently associated with various 

 species of Aristida. It belongs to the ^Chlorideae'''' , and is mostly 

 dioecious, the two sexes being very unlike. *) The leaves are 

 plane, and the lower face has narrow furrows between the ribs, 

 while the upper is nearly smooth. There are many short papillae 

 on both faces of the blade outside the subepidermal stereome, 

 and long unicellular, pointed hairs are scattered over both faces. 

 Between the ribs occur large bulliform cells, which pass gradually 

 over into a single layer of colorless tissue, extending to the lower 

 epidermis. The outer cell- wall of the epidermis is strongly thicke- 

 ned on both faces and covered by a distinct smooth cuticle. 

 Stomata occur on the sides of the furrows and near the bulli- 

 furm cells on the upper face. They are surrounded by papillae, 

 but are otherwise level with the epidermis. There is not much 

 siereome in the leaf, and it forms only small groups above and 

 below the mestome bundles, mostly separated from the parenchyma- 

 sheath by the palisades, and a small, isolated group is located 

 on the leaf-margin. The mesophyll is confined to the ribs, where 

 it surrounds the orbicular mestome-bundles as radially arranged 

 palisades. These border on the single parenchyma-sheath, which 

 is large-celled, somewhat thick-walled, and contains starch. 



The mestome-bundles are thus surrounded by only one paren- 

 chyma-sheath, which is continuous in all the bundles, Inside is a 

 true mestome-sheath,whichpresents somemodifications: The cell- walls 

 are heavily thickened in the larger bundles, but only around the 



*) The best figure of this peculiar, little grass is given by Engelmann 

 in Iiia paper: „Two new dioecious grasses of the United States." (Transact. 

 St Louis Acad. Sc. Vol. I. St. Louis 1859. i). 431.) 



