CRYPTOGAMIA— FILICES. Equisetum. 337 



2. Ya, fluviatile. Great Water Horsetail. 



Sterile stems beset with innumerable, roughish, doubly 

 angular, branches ; flowering ones unbranched, with 

 numerous, crowded, deeply toothed sheaths. 



E. fluviatile. Linn. Sp. PL 1517. Willd. v. 5. 2. Fl. Br. 11 04. 



Engl. Bot. V. 29. t. 2022. Hook. Scot. p.2.\6\. Bolt. Fil. C6. 



^.36,37. 

 E. n. 167-5. Hall. Hist. V. 3. 1. 



E. Telmateia. Ehrh. Beitr. v. 2. 159. Crypt. 3\. Fl. Dan. t. 1469. 

 E. eburneum. Roth. Catal. v. 1. 129. 

 E. majus. Raii Syn. 130. Ger. Em. 1 1 13./. 

 E. primum. Mat}h. Falgr. v. 2. 373./. Dalc.ch Hist. 1069./. 

 E. palustre longioribus setis. Bauh. Tlieatr. 241./. 

 Hippuris. Lob. Ic. 793. f. 

 H. major. Dod. Penipt. 73. f. 



In watery places, about the banks of rivers and lakes. 



Perennial. April. 



This is by far our largest species, differing from the foregoing in 

 bearing the fructification on a separate stent from the branched 

 or whorled /ro/?r/; as is likewise the case with the following one, 

 E. arvense. All the others, hitlierto observed in Britam, have 

 terminal catkins, at the tops of the fronds. The sterile stems of 

 E.Jluviatile are quite erect, at least a yard high, often much 

 more, furnished from top to bottom with whorls ot numerous, 

 long, slender, minutely rough, distantly jointed, not often 

 divided, branches, whose four angles have each a longitudinal 

 furrow, first noticed by Mr. J. D. Sowerby, constituting a clear 

 distinction between the present species and the next. Each 

 joint is crowned by a small sheath, having four or five long pide 

 teeth. The large cylindrical catkins stand uj^on much sliorter 

 unbranched stems, appearing before the others, invested with 

 nine or ten pale, tubular, ribbed sheaths, nearly close together, 

 each of which terminates in a fringe of long, upright, brown 

 teeth, amounting, as Ilaller observes, to forty. In the next 

 species they are scarcely half so many, and the sheaths are but 

 about three or four, rarely five, on each stem. 



3. E. arvense. Corn Horsetail. 



Sterile stems beset with r(Mighisli, mostly simple, angular 

 branches; flowering ones unbranched; their sheaths 

 distant, deeply toothed. 



E. arvense. /w/i/i. .S>. /V. 15 16. H'llld. v.5. \. Ft. Br.\\03. Engl. 



Bot. V. 29. /. 2020. Hnok. Scot. />. 2. 160. Curt. Land. fasc. 1. 



t. 61. Bolt. Fit. 62. /. 34. Ehrh. Crypt. 21. 

 E. n. 1676. Hall. Hist. v. 3. 2. 

 E. arvense, longioribus sells. Raii Syn. \3i). Bauh. Tluair.2\7 . f. 



roL. IV. z 



