84 Braun and Engelmann's North American Equiseta. 



(Fremont,) and the North West coast, (Chamisso.) (5. Germa- 

 ny, Kentucky, (Short,) Missouri, in fertile woods, y. Germany, 

 Missouri, in dry pastures, road sides. $. Very rare, in Germany. 



2. E. eburneum, Schreb. — Sterile stems very smooth, ivory 

 white ; sheaths consisting of about thirty bicarinate leaves, sepa- 

 rated by deep commissural furrows ; carinas of the simple branch- 

 es again deeply furrowed, scabrous ; their sheaths consisting of 

 four (sometimes five) bicarinate leaves, with herbaceous erect 

 subulate fragile teeth. Fertile stems simple, sheaths consisting 

 of obsoletely 3-carinate leaves, with lanceolate subulate teeth. — 

 E. Telmateja, Ehrh. E . jluviatile, Smith, Willd., Vaucher, not 

 HofTm. E. decumanum, Pallas, (Siberia,) E. macrostachyon, 

 Poir. (Barbary.) 



@. frondescens. Fertile stems persistent, producing herbace- 

 ous branchlets. 



y. serotinum. The usually sterile stems with late fructifica- 

 tion. 



Hab. Europe, Asia, North Africa and North America, (on Lakes 

 Erie and Superior, Torrey, according to Beck's Botany.) 



The sheaths of the fertile and sterile stems are formed by from 

 20 to 40 leaves, generally 24 to 36. Sterile stems from 2 to 5 

 feet high. 



tt Metahola, (Subvernal Equiseta) : fertile stems persistent and producing 

 herbaceous branches after fructification. 



3. E. sylvaticum, Linn. — Sterile (and finally also the fer- 

 tile) stems doubly branched, the branchlets curved downwards ; 

 stems grooved, fertile ones nearly smooth ; carinas of the sterile 

 ones scabrous, in two rows ; sheaths consisting of about twelve 

 1-carinate leaves with shallow commissural furrows between 

 them ; their scarious elongated points partly connate, so that the 

 sheaths appear to be 3- or 4-lobed ; carinas of the branches slight- 

 ly furrowed, somewhat scabrous; carinas of the branchlets com- 

 pressed, smooth, their sheaths funnel-shaped, consisting of 4 or 5 

 (on the branches) and 3 (on the branchlets,) 1-carinate leaves 

 with lanceolate-acuminate divergent teeth. 



Hab. Europe, Asia, North America, from Labrador (linger,) 

 to Massachusetts, (Oakes,) Pennsylvania, (Muhlenberg,) Virgin- 

 ia, (Pursh,) and Ohio, (Riehl.) 



The sheaths of the stem are formed by 8 to 17 (generally 10 

 to 14) leaves whose points are connected in 2 to 4 or more lobes, 



