Barren stem of Equisetum arvense.
This species is by far the commonest of all the Horsetails, and is very frequently to be found on embankments in fields and by the sides of roads. The plant, which dies down in the winter, starts its growth quite early in the year with the development of the fertile stems. These rise straight up from the branching root-stock, and are generally about five or six inches in height. The stem, which is of a very pale colour, is of rather a succulent nature; it is hollow in the centre and in a certain way reminds one of bamboo. At intervals there are certain sheaths which are divided into a number of teeth with very sharp points. The cone-like fructification is about an inch in length and bears a number of peltate scales to which the spore capsules are attached. The spores are ready for dispersal in the month of May. Just about this time the barren stems put in an appearance. These rise to the height of two feet, or even more, and have many whorls of spreading branches which in their turn may again be branched. It is these branches which carry on the real vegetative work of the plant. For the real leaves we must examine the sheaths, which with their wedge-shaped teeth are to be found at the stem joints. The teeth are the only free portions of the leaves of the Horsetails. It is interesting to note that in each whorl the branches are equal to the number of leaves and are alternate to them. The stem of the barren branches of the Field Horsetail is slightly marked with furrows, which vary in number. The branches are usually only four-furrowed, and have sheaths with the same number of teeth.
The whole of the barren portion of the Field Horsetail is very rough to the touch. This is due to the fact that the plant is covered with tiny flinty particles. That the measure has a protective value is very evident, for cattle have hardly ever been known to eat the plant.
Equisetum maximum. In this case the specific name, of course, means great, and has reference to the fact that the species is the largest of all the kinds. In some old books this species is given as E. Telmateia and E. fluvialis. The Great Horsetail.
Fertile cones of Equisetum maximum.
This is by far the most striking of all our native Horsetails. As a rule the plant grows in a damp situation, and it then assumes handsome proportions. The fertile stems appear on the scene about April, and these do not as a rule exceed a foot in height. They are very succulent, and have loose sheaths which have about thirty or forty teeth. The sheaths are green at the lower, and brown at the upper part, being distinctly marked with lines. The fertile cones are three or four inches long and possess a very large number of scales. The barren stems are remarkable for their erect growth, and in a fine specimen these may be four or five feet in height. The stem bears numerous whorls of branches, and these branches may show yet further divisions. As a rule each whorl has thirty or forty branches apiece. On the upper part of the stem the whorls are very close together, but they are more widely separated at the lower portion. The main stems, which taper towards the apex, are marked with lines, and at intervals are enclosed in sheaths; these have long teeth and fit the stem very closely. The branches are rough to the touch, and have sheaths which end in four or five teeth; each tooth in this case is prolonged into a bristle which has two toothed ribs. This is a feature by means of which it is always possible to distinguish the Great Horsetail from any other species. Now and again stems have been found which, whilst bearing fertile cones, at the same time branch in the manner to be observed in the case of the barren stems.
The Great Horsetail is widely distributed and is sometimes very abundant, though it is not so common as some of the other species of Equisetum.
Equisetum pratense. In this case the specific name is a Latin word which means “growing in a meadow.” In some books this plant is known as E. umbrosum. The Shade or Blunt-topped Horsetail.