260 Class XXIV. Order I. 



The fruitful stems of this plant appear in April, and soon 

 decay. They are erect, smooth, furrowed, and without branch- 

 es, their joints surrounded with large, swelling sheaths, which 

 end in long, blackish teeth. Spike terminal, oblong-ovate, with 

 a membranous border below it. The barren stems are taller and 

 more durable ; they are erect, or ascending at base, roughish, 

 their joints furnished with sheaths and large whorls of simple, 

 ascending branches. These branches are three or four cor- 

 nered, with sheaths at their joints, ending in the same number 

 of teeth. Moist ground, South Boston Perennial. 



BQUISETUM STLVATICUM. L. Wood HorsetaiL 



Branches compound, curving downward, rough. 



The fertile stems are erect, round, furrowed, jointed. Joints 

 invested with large, loose sheaths, which divide into a number 

 of broad teeth at top. Branches very slender, in a whorl pro- 

 ceeding from the upper joint, immediately below the sheath, 

 divaricated and curving downward. The second joint from the 

 top is furnished with a whorl of shorter branches, and some- 

 times also the third. Ament ovate, terminal, composed like 

 the rest, of peltate, hexagonal scales. The barren stems are 

 smaller and higher, their joints all furnished with whorls of 

 branches, which are much longer, and considerably subdivided 

 Low grounds, Roxbury, Cambridge. Perennial. 



