Ord. 1.] CRYPTOGAMIA FILICES. 215 



6. L. alpinum, 4. 234. (Savin-leaved CO Stems prostrate. Branches 

 erect, clustered, forked, level-topped. Leaves acute, keeled, im- 

 bricated in four rows. Scales of the spikes ovate-lanceolate, flat. 

 Lofty mts. If, 8. A handsome evergreen, of a glaucous hue. 



478. EQUISETUM. Horse-tail. 



1. E. sylvaticum, 27. 1874. (Wood H.) Branches compound, curved 



downwards, smooth. 

 Moist shady woods.lf. 4, 5. 1 — 1 If. with many whorls. Very eleg. 



2. E.Jfuvidtile, 29. 2022. ( Water H.) Sterile stems beset with innu- 



merable, roughish, doubly angular branches ; flowering ones un- 

 branched, with numerous, crowded, deeply toothed sheaths. 

 Watery pi. If. 4. The largest sp. Fl. stems a span. Catk. large. 



3. E. arvense, 29. 2020. (Corn H.) Frond attenuated upwards. 



Sterile stem slightly scabrous, with 12 — 14 furrows. Teeth of 

 the sheath lanceolate-subulate. Branches simple, rather spread- 

 ing. Fertile stem without branches ; its sheaths remote, loose. 

 Moist corn-fields. If. 3 — 4. Fl.-stems a span high ; pale br. 

 *3. E. Drummondii, Suppl. 2777. (Blunt-topped H.) Frond very 

 obtuse at the extremity. Sterile stem, especially upwards, rough 

 with prominent points and about 20 striae. Teeth of the sheath 

 appressed. Branches simple, spreading. Fertile stem without 

 branches ; its sheaths approximate, appressed, with subulate 

 teeth. 

 Moist banks, Scotl. and Irel. If. 4. Very distinct from the preceding. 



4. E. palustre, 29. 2021. (Marsh U..) Stem deeply furrowed, 



branched throughout, with a terminal catkin ; branches simple, 

 erect, roughish, with simple angles. 

 Marshes. If. 6, 7. Sheaths green ; whitish at the top. Catk. small. 



5. E. limosum, 13. 929. (Smooth H.J Stem partially naked, striated, 



smooth as well as the branches. Catkin terminal, elliptical. 

 Marshy watery pi. If. 6, 7. Stem 2f. Br. short, not numer. Catk. 

 large. 



6. E. hyemale, 13.915. (Rough H. Shave-grass. ) Stem naked, very 



rough, mostly branching at the base. Sheaths whitish ; black at 

 the top and bottom ; teeth deciduous. Catkin terminal. 

 Boggy woods. If . 7, 8. 1 — 2/. deep glauc. green. Catk. small, br. 

 The bark, abounding in silex, is used for polishing ; being im- 

 ported under the name of Dutch rushes. 



7. E. variegdtum, 28. 1987. (Variegated H.) Stem naked, very 



rough, branched at the base. Sheaths black ; with white, mem- 

 branous, lanceolate teeth. Catkin terminal. 

 Wet sandy gr. If. 7. Smaller and more slender. Catk. blackish. 



479. PILULARIA. Pillwort. 



1. P. globul'tfera, 8. 521. (Creeping Pillwort. Pepper-grass.) 



Watery gravelly pi. If. 6, 7. Stems thread- sh. creeping, partly 



