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VARIETIES. 



No varieties, in the common acceptation of the term have 

 been noticed of this, or any other of the true Equiseta with the 

 exception of variety borcalc of B. arvense, Numerous forms and 

 freaks have, however, been noted, of which I have seen the fol- 

 lowing from America: 



1. Intermedium A. A. Eaton. Stems short, 3-8 inches 

 high, decumbent at base, rarely erect, bearing a few basal 

 branches, or with the 3-6 lower internodes bearing verticils of 

 2-6, these again rarely bearing branchlets ; upper 2-6 internodes 

 naked, ending in a normal spike. Flats on banks of Merrimac 

 river" at Amesbury, Mass. Caused by a deposit of 6-8 inches of 

 sand by freshets : in and about little pools of water. 



This variety grows among litorale and was at first taken to 

 be a fertile form of that species, as it greatly resembles var. 

 humile. It can be separated from that variety only by taking 

 sections of the stem. It will then be seen that this has thin walls 

 and no vallecular holes, while the other has thicker walls and 

 vallecular holes. The sheaths of this are a little shorter and 

 tighter than the other, the stomata narrower and more num- 

 erous. It has persisted unchanged in this locality for five 

 years. 



2. Uliginosiim Muehl. Stems slender. 9-1 1 angled, naked 

 or rarely branched, usually all sterile. Not suffifficiently distinct 

 from the next. Described from plants collected in Pennsylvania 

 by Muhlenberg. It grows usually on hard, often gravelly soil. 

 Uncommon. Gravelly river banks. Ft. Fairfield, Me. Fernald, 

 shores of Merrimac at Amesbury. Mass. 



3. Limosum (L) Gilbert, (var. Linnaeanum Doell). Stems 

 naked or with a few secondary stems at fruiting time, often de- 

 veloping a few true branches in the upper internodes after decay 

 of the fruit-spike. Deep mud. where inundated by the tides. 

 Merrimac river, Newburyport, Mass., and very common else- 

 where in similar situations. Originally described as a species by 

 Linnaeus, but as the next form precedes it in Species Plantarum 

 that retains the name. I am not certain if Mr. Gilbert is the first 

 to print it as a variety of Huviatilc. 



4. Verticillatum Doell. Stems bearing more or less regular 

 verticils of branches: the typical form of the species appearing 



