THE PHYTOLOGIST. 



No. XVIII. 



NOVEMBER, MDCCCXLII. 



Price Is. 



Art. XCII. — Description of Equisetum hyemalCi Mackaii and vari- 

 egatiim^ as found on the hanks and in the bed of the River Dee; 

 with addition'al observations. By J. B. Brichan. 



Equisetum hyemale. 



Root creeping, jointed, branched. Stems several from one branch 

 of the root, or branched at the base, one to three feet high, or upwards, 

 stout, erect or decumbent, articulated and fluted, occasionally throw- 

 ing out catkins or very small branches near the top. Ridges or 

 furrows fourteen to twenty-one in number, in luxuriant specimens 

 twenty-eight ; ridges grooved, and, as well as the furrows, grained like 

 a file. Sheaths widest at top, at first pale green, with a black crenate 

 rim ; afterwards entirely black ; ultimately white, with a broad black 

 band at the base, the rim remaining black as before. The uppermost 

 sheaths of the root generally, and the upper and lower of the younger 

 stems occasionally, bear black, membranous, flexuose, deciduous teeth 

 or bristles. The sheath of the catkin is invariably and persistently 

 toothed. Catkins terminal, more rarely lateral, and in that case either 

 single or in opposite pairs. 



Equisetum Mackaii. 



Root creeping, jointed, branched. Stems several from one branch 

 of the root, or branched at the base, slender, often filiform, erect or 

 decumbent, one to two and a half feet high, consisting of articulations 

 from one to two and a half inches in length. The older stems fre- 

 quently throw out long slender branches, which generally bear cat- 

 kins. The stems are fluted, the ridges grooved, and both ridges and 

 furrows grained as in E. hyemale. Number of ridges or furrows eight 

 to twelve. Sheaths cylindrical, at first pale or yellowish green, with 

 a narrow black band immediately under the teeth ; ultimately wholly 

 black, with the lower border of the black entire. Teeth equal in 

 number to the ridges, membranaceous, white at the edge, long and 

 tapering, terminating in a flexuose bristle which is generally black, 



2h 



