308 



tory of Fossil Vegetables, as are, indeed, all the parts of their organization : 

 see Tables 11 and 12 of that work. This ingenious writer entertains the 

 opinion that the green body which is known to be the sporule, is a naked ovu- 

 lum, and the 4 swollen filaments that surround it 4 grains of pollen united in 

 pairs to the base of the ovulum. It is probable that the nearest approach to 

 the structure of stamens and pistils does take place here, and that, considering the 

 analogy between the thecae of Equisetum and the lobes of the anther of Coni- 

 fers, and the filaments of the former and the quaternary grains of pollen of Cy- 

 cas, the parallel drawn by M. Brongniart is just ; but it must, at the same 

 time, I think, be admitted, that it is very doubtful whether, in this order, the 

 parts are any thing more than representatives of the stamens and pistils, without 

 the power of performing their functions. 



The germination of the sporules has been explained, both by Agardh and 

 Bischoff. 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 confervoid, cylindrical, obtuse, articulated, torulose 

 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 Bischoff {Nov. Act. Acad. JV. Cur. 14. t. 44.) 

 is not materially different : he finds the confervoid threads or numerous pro- 

 cesses of cellular developement go on growing and combining, until a consider- 

 able 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 Equise- 

 tum, at once completely organized, with its air-cells, its central cavity, and its 

 sheaths, the first of which is formed before the elongation of the stem, out of the 

 original cellular matter. 



Geography. From the researches of M. A. Brongniart, it appears indis- 

 putable that plants very nearly the same as these in their organization formed 

 part, and a considerable part too, of the original vegetation of the globe ; not, 

 however, puny species, such as those of our days, with feeble stems, scarcely 

 ever exceeding 3 or 4 feet in height, but gigantic vegetables, many yards long. 

 If, indeed, certain striated fossils of the coal fields should be referable to this 

 family, it will be found that some of them must have been vast trees. In our 

 days they are found in ditches and rivers in most parts of the world, within and 

 without the tropics ; they have not, however, been yet seen in New Holland. 



Properties. None of importance in a medicinal point of view ; they are 

 said to be slightly astringent and stimulating, and have even been recommend- 

 ed as diuretics and emmenagogues ; they are, however, not now employed. 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 below their cuticle. According to the observations of Dr. John of Ber- 

 lin, 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. 

 Jameson 1 s Journal, Jan. 1830, p. 102. The quantity of silex contained beneath 

 the cuticle of Equisetum hyemale is so great, that Mr. Sivright succeeded in 

 removing the vegetable matter and retaining the form. Grev. Fl. Edin. 214. 

 On subjecting a portion of the cuticle of Equisetum hyemale to the analysis of 

 polarized light under a high magnifying power, Dr. Brewster detected a beau- 

 tiful arrangement of the siliceous particles, which are distributed in two lines 

 parallel to the axis of the stem, and extending over the whole surface. The 

 greater number of the particles form simple straight lines, but the rest are 

 grouped into oval forms connected together like the jewels of a necklace, by a 

 chain of particles forming a sort of curvilinear quadrangle, these rows of oval 

 combinations being arranged in pairs. Many of those particles which form the 



