=201. Size and kinds.= The unit size of quadrat is the meter, and when the term is used without qualification, it refers to the meter quadrat. To make them strictly comparable, and exactly divisible, unit quadrats are always grouped in squares; thus a major quadrat is a square of four units, and a perquadrat one of sixteen units, or four meters square. Quadrats of greater size are necessary in woodland and forest, where the rule, however, is that the woody plants alone are recorded for the whole quadrat, the herbaceous growth being listed or mapped for but one or two representative units. For special purposes, quadrats of 3, 5, 6, etc., meters may be used, but they are much less convenient. Quadrats are further distinguished with respect to their use. A list quadrat is one in which the plants are merely listed and the number of individuals of each species indicated. Chart quadrats are those in which the area concerned is accurately mapped on plotting paper. Both list and chart quadrats are rendered permanent by careful labeling, so that their changes can be followed from year to year. The greater value of the chart causes practically all permanent quadrats to be of this type, and for the same reason only permanent chart quadrats are converted into denuded ones. =202. Tapes and stakes.= The lines for marking out quadrats are made of strong white tape, ⅝ inches wide. This is doubled and sewed firmly at both edges. Under moderate stretching, the tape is carefully marked off into decimeters, and eyelets 5 mm. in diameter are set in at each end and at the marks. This can readily be done by any shoemaker at slight expense. The usual lengths are one and two meters, as these are most frequently used, and they can also be easily combined to make larger quadrats. The tapes are slightly longer than one meter in order that the distance between the end eyelets may be exact. The tapes of the larger forest quadrats should be divided into lengths of one meter, as these permit ready plotting and also make it possible to interpolate a meter quadrat for the study of the undergrowth at any point. The intervals of the tape are numbered from left to right, as conspicuously and clearly as possible. For this a waterproof ink or paint is very desirable. For holding the tapes in position, hatpins, nails, and meat-skewers have been used with more or less satisfaction. The ideal stake, however, is one which holds the tape close to the ground, and can be readily moved. It is merely a stout wire, 3 mm. in diameter and 8 inches long, looped at the top, sharpened at the tip, and with a small ring of solder 3 inches from the tip.