318 
Upon the whole, however, I think we must admit that Equisetacese are more 
like flowering than flowerless plants ; and it seems to me most advisable to 
consider them a degeneration of Coniferse, to which they have so much re- 
semblance, rather than a race in affinity with Ferns, with which they really 
have no resemblance. They are apparently to other Gymnosperms what Cera- 
tophyllum is to Exogens and Lemna to Endogens. 
The germination of the sporules has been explained, both by Agardh and 
Bischofl’. The former {Aphor. 120) describes it thus: From 3 to 14 days 
after they are sown, they send down a filiform, hyaline, somewhat clavate, 
simple root, and protrude a confers'oid, cyhndrical, obtuse, articulated, toru- 
lose thread, either 2-lobed (in E. pratense) at the apex, or simple (in E. 
palustre). Some days after, several branches grow out and are agglutinated 
together, forming a body resembling a bundle of confervoid threads, each of 
which pushes out its own root. The account of Bischofl" {Nov. Act. Acad. 
N. Cur. 14. t. 44.) is not materially different : he finds the confervoid threads 
or numerous processes of cellular developement go on growing and combining, 
until a considerable cellular mass is formed ; then this mode of developement 
ceases, and a young bud is created, which springs up in the form of the stem of 
the Equisetum, at once completely organised, with its air-cells, its central ca- 
vity, and its sheaths, the first of which is formed before the elongation of 
the stem, out of the original cellular matter. 
Geography. Found in ditches and rivers in most parts of the world, 
within and without the tropics. 
Properties. None of importance in a medicinal point of view ; they are 
said to be slightly astringent and stimulating, and have even been recom- 
mended as diuretics, and emmenagogues ; they are, however, not now em- 
ployed. In economical purposes they are found highly useful, for polishing 
furniture and household utensils ; a property which is due to the presence of 
a great quantity of silex in their cuticle. According to the observations 
of John of Berlin, they contain full 13 per cent, of siliceous earth. Ed. P. J. 
2. 394. The ashes have been found by chemists to contain half their weight 
of silica. Jamesons Journal, Jan. 1830, p. 101. The quantity of silex con- 
tained in the cuticle of Equisetum hyemale is so great, that Sivright suc- 
ceeded in removing the vegetable matter and retaining the form. Grev. FI. 
Edin. 214. On subjecting a portion of the cuticle of Equisetum hyemale to 
the analysis of polarised light under a high magnifying power, Brewster de - 
tected a beautiful arrangement of the siliceous particles, which are distributed 
in two hnes parallel to the axis of the stem, and extending over the whole sur- 
face. The greater number of the particles form simple straight lines, but the 
rest are grouped into oval forms connected together hke the jewels of a neck- 
lace, by a chain of particles forming a sort of curvilinear quadi’angle, these 
rows of oval combinations being arranged in pairs. Many of those particles 
which form the straight lines do not exceed the 500th of an inch in diameter. 
Brewster also observed the remarkable fact, that each particle has a regular 
axis of double refraction. In the straw and chaff of Wheat, Barley, Oats, and 
Rye, he noticed analogous phenomena ; but the particles were arranged in a 
different manner, and displayed figures of singular beauty. From these 
data it is concluded that the crystalline portions of silex and other earths, 
which are found in vegetable tissues, are not foreign substances of acci- 
dental occurrence, but are integral parts of the plant itself, and probably 
perform some important function in the process of vegetable life. Grevill. FI. 
Edinens. 214. 
GENUS. 
Equisetum, L. 
