28 
EQUISETACE^. 
M. Vaucher, in his introductory remarks on the genus, aptly 
cites his Equisetum multiforme as an instance of characteristic 
liability to variation. After mentioning that the Equiseta gene- 
rally occur on the banks of streams and in damp places, as well 
as in the water, he says they are occasionally even met wdth 
in sandy places that are not watery, such is the case with Equi- 
setum multiforme : this species appears strongly influenced by 
the properties of the soil in which it grows, for sometimes it 
throws out but a small number of slender and short branches, 
at other times, on the contrary, and especially when in a more 
fertile soil, we find issuing from the principal stem, branches not 
only much longer but much more divided, so much so indeed 
that it has been thought it could not then be referred to the same 
species.’'^ 
The roots and rhizoma present no characters by which I can 
distinguish this plant from that previously described : in both, 
these parts are black, the roots being tortuous, much divided, 
and often clothed wdth minute and matted fibrillse : the stems 
are very long, generally erect, nearly straight, and jointed as in 
the former species : the figure at p. 25, shows a stem divided into 
six portions, its size and the relative length of the internodes 
having been copied with scrupulous accuracy. Both the inter- 
nodes and sheaths are striated ; the striae vary in number from 
eight to twelve, or even fourteen. The stem is hollo wq with the 
Cette variete /3. se trouve sou vent reunie a la premiere, et I’on peut facilement 
observer des ecbantillons qui presentent toutes les nuances intermediaires. 
Ordinairement la Prele rameuse se rencontre dans des terreins plus riches et 
plus favorables a la vegetation. — ‘ Memoires de la Societe de Physique et d’His- 
toire Naturelle de Geneve.’ i. 379. The plant is the Equisetum mmosum of 
Schkuhr, p. 178, tab. 172, h. 
^ On en rencontre meme dans les terreins sablonneux et non humectes, 
comme par exemple la Prele multiforme ; mais cette derniere espece paroit 
etre fortement influencee par la nature du terrein dans lequel elle croit, car 
tantot elle ne developpe qu’un petit nombre de tiges greles et fort courtes, tan- 
tot au contraire, et surtout lorsqu’elle sort d’un terrein plus riche, on voit sortir 
de la touffe principale des tiges beaucoup plus grosses et plus ramifiees, qu’on 
croiroit ne point appartenir a la meme espece. — Id. 333. 
