THE GENUS EQUISETUM IN NORTH AMERICA. 



By A. A. Eaton. 



FIFTEENTH PAPER. 



Varieties of E. Hiemaee. 



1. Intermedium A. A. Eaton. Stems I to 4 feet high, 1 to 4 

 lines in diameter, simple or ultimately branched, 20 to 30 angled, 

 rough with transverse bands of silex or becoming smoother by 

 a later deposit covering them; sheaths longer than broad, ampli- 

 ated, green excepting narrow black and white incurved limb, or 

 exceptionally with other black and white markings ; leaves keeled 

 below the middle, flat and often centrally grooved above; teeth 

 thin, brown, hyaline-bordered, deciduous or persistent ; anat- 

 omy of hiemale as previously described. New York, Michigan 

 and westward. Common west of the Mississippi, being an 

 important forage crop in some States. The anomalous laeviga- 

 ta hi collected by Rydberg at Thedford, Neb., No. 1283 (Cont. 

 Nat. Herb. Ill, 194), is this variety, as is the plant referred to 

 under the name of variegatum by V. K. Chestnut (Cont. Nat. 

 Herb. VII, 304), as used for various unimportant purposes by 

 the Indians of Mendocino County, California. He also men- 

 tions the fact that horses eat it even when grass is abundant. 



2. Texanum Milde. Stems erect, very slender, somewhat 

 rough, 10 to 12 angled, hardly 1 foot high, dirty green ; sheaths 

 elongated, slightly widened, 2 to 2 1-3 lines long and 1 1-3 wide, 

 concolorous, leaves flat, centrally grooved and 4 angled above 

 and centrally ridged below; teeth persistent, flexuous, white with 

 red-brown center, lance subulate, smooth, only the lowermost 

 three sheaths red-brown ; ridges convex ; carinal bast 7, vallecu- 

 lar 4, cells high, vallecular holes transverse oval ; stomata rows 

 separated by 7 to 8 cells, grooves naked, lumen of epidermal 

 cells very wide, angles with broad, short bands, never with two 

 rows of tubercles. Texas, Chas. Wright. 



This is Milde's description. I have never seen this plant. 

 Milde states that it is a very peculiar plant that equals the 

 weakest specimens of var. Moorei, but differs greatly from it, 

 and he asks if it may not be the young stage of a larger species. 



3. Herbaceum var, nov, Cespitose, decumbent, ascending or 



