522 EQUISETACEjE. [Equisetum. 



2. E. pratense, Ehrh. ; barren stems scabrid 8-20-grooved, branches 

 spreading, sheaths of fruiting stems close-set, ribs of teeth not reaching 

 the tip. E. umbro'sum, Willd. ; E. Drummon'dii, Hook. 



Marshes, rare, from Caithness to York ; ascends to 1,200 ft. in N. England ; 

 N. Ireland ; frt. April. — Closely allied to E. arven'se, but greener, less 

 glaucous, more scabrid, with more numerous ribs and branches ; the barren 

 stem terminates in an abrupt brush of branches as in E. sylvat'icum. Barren 

 stems 1-2 ft., sometimes bearing a cone, slender, abrupt ; branches simple, 

 slender, usually spreading, 3-4-gonous, sheaths very short ; fertile much 

 stouter, sheaths very lax, funnel-shaped. Cones |-1| in. — Disteib. Europe 

 .(Arctic) N. of the Alps, Italy, Siberia, N. America. 



3. E. maximum, Lamk. ; barren stems 20-40-grooved, branches sub- 

 erect, sheaths of short fruiting stems close large loose, teeth 2-ribbed. E. 

 Telmetei'a, Ehrh. ; E. Jluviat'ile, Sm., not L. 



Bogs, ditches, &c, from Skye, Lanark, and Edinburgh southd. ; ascends to 

 1,200 ft. in Yorkshire ; Ireland ; Channel Islands ; frt. April. — Barren stems 

 3-6 ft., ^ in. diam. ; branches 4-gonous, slender, erecto-patent, sheaths very 

 short; fertile 8-10 in., §-£ in. diam. including the large lax sheaths. Cone 

 2-3 in., obtuse. — Distrib. From Denmark southd., N. Africa, N. and W. 

 Asia, N. America. 



** Fruiting and barren stems subsimilar, simple or branched. 



4. E. sylvat'icum, L. ; stems 10-1 8 -grooved, branches recurved or 

 deflexed divided, stem-sheaths lax, teeth long obtuse, teeth of branch - 

 sheaths 3-ribbed to the tip. 



Copses and hedgebanks, from Shetland to Devon and Kent ; ascends to 

 2,700 ft. in the Highlands ; Ireland ; frt. April-May. — Eeadily recognised 

 by the elegant appearance of the whorls of compound recurved branches. 

 Stem 1-2 ft., nearly smooth. Teeth of branch-sheaths 3-5, large. Cones 

 |-1 in., short, ovoid-oblong, obtuse. — Distrib. Europe, N. Asia, N. 

 America. 



5. E. palus'tre, L. ; stems 5-1 2-grooved, branches simple, stem-sheaths 

 short appressed, teeth acute, tips membranous. 



Wet places, 1ST. to Shetland ; ascends to 2,500 ft. in the Highlands ; Ireland ; 

 Channel Islands; frt. June-July. — Very variable. Stem 6-18 in., deeply 

 furrowed, branched throughout, slightly rough. Cones short, blunt, those 

 on the branches small. — Distrib. Europe, N. and W. Asia, N. America. 

 — Yar. polysta'chya bears cones on the branches also.— -Yar. alpi'na (or 

 subnu'da) is a stunted state. 



6. E. limo'sum, L. ; stems smooth faintly 10 -30 -striate, branches 

 simple erect or 0, sheaths short appressed, teeth short rigid. 



Sides of lakes and ditches, N. to Shetland ; ascends to 2,500 ft. in the High- 

 lands; Ireland; Channel Islands; frt. June-July. — Easily distinguished by 

 the hardly furrowed stems, and close and short sheaths. Stems stout, 1-3 ft., 



