Ata: 
A 
“ho? 
i 
A CA em er 
Araxart cA AG/ ie 
j stipulaceum, Vaucher, and #. ‘faselliferiin, Kunze.) 
ala, : 
X - ‘ 
as — 
* 
86 Braun and Engelmann’s North American Equiseta. 
species i is EH. Bogotense, Humb., Bonpl. and Kunth. (Syn. Z. 
6. E. troosum, Linn.—Stems tall, erect, generally above with — 
simple branches, the sterile ones much elongated ; grooved, near- 
ly smooth ; vallecular air-cavities none, the carinal ones small, 
the central cavity very large; sheaths adpressed, consisting of — 
about eighteen 1-carinate not furrowed leaves, with linear acute — 
blackish teeth nearly destitute of a membranaceous margin; — 
branches somewhat scabrous; sheaths herbaceous, consisting of — 
about six leaves with linear-setaceous points.—E. limosuwm and — 
E. fluviatile, Hoffm. and other ars = ee Sti Ehrh. 
8. minus, A. Braun. St us, sheaths — 
consisting of about eleven leaves. _E. uliginosum, Muhlenb., 
Willd. 
y. poLystacnyum. With numerous short verticillate, florife- 
rous branches. 
Hab. In ditches and swamps in Europe. In the United States — 
in Pennsylvania, ( Wolle,) New York, (H. E'aton,) and Wiscon- 
sin, (Lapham in herb. Short.) 8. in North America, Newfound- — 
land, (La Pylaie,) Northern States, (Beck’s Botany,) Pennsylva- 
nia, (Muhlenberg,) Virginia, (Pursh.) Also in Germany in peat — 
morasses, (A. Braun.) Easily distinguished from E’. palustre, — 
by the structure of the stem and by the teeth; though at first 
sight var. 8. considerably resembles some forms of the former. — 
The sheaths are composed of 10 to 22 leaves, commonly 17 to 
20, in the American specimens examined by me of 15 to 21, in | 
B. of 10 to 12 leaves. Rhizoma never tuberous. The branches | 
are generally developed after sr uctificdtion! | 
$2. Equisera STICHOPORA, ( Winter-E'quiseta): Stomata dis- : 
posed in two distinct ranges on each side of the groove; each — 
range formed by one or more rows of stomata. (All the — 
known species of this division, have hardy evergreen stems.) 
Most of the tropical Equiseta, as well also as some of the most _ 
northern species, (#. scirpoides and EH. boreale,) belong to this — 
large and very difficult division. They all contain more silex 4 
beneath the cuticle than the #. speiropora, which accounts for 
their hardness and durability. Their distinguishing characteris- 
tic is the disposition of the stomata in two ranges, separated by 
a free interstice. In the European and North American species, 
ee 
Pesci a ea 
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