522 EQUISETACEJS. [EQUISETUM. 



2. E. praten'se, 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 f-l| in. DISTRIB. 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. fluviat'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 stem* 

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

 short ; fertile 8-10 in., f-f 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 10-18-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 

 f-1 in., short, ovoid-oblong, obtuse. DISTKIB. Europe, N. Asia, N. 

 America. 



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

 short appressed, teeth acute, tips membranous. 



Wet places, N". 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. 

 VAR. polysta'chya bears cones on the brauches 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- 

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

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



