=208. The chart= used is a decimeter square, and the scale is consequently 10 : 1. It is outlined on centimeter plotting paper, and the centimeter squares are numbered at the edges to correspond to the intervals of the quadrat, i. e., the top and bottom lines are numbered from left to right, and the side lines from top to bottom. These outlines are ruled in quantity and used as needed, or the forms can be furnished by the printer. In practice, a special quadrat book the size of the chart has been used. The need of a second book may be avoided by outlining two charts on the plotting sheet, and filing the latter in the field record book. In the few cases where 2–meter quadrats are desirable, four charts are used, care being taken to label them so that they can be combined whenever necessary. Ten-meter quadrats are recorded on the decimeter chart also, each meter interval corresponding to a centimeter, i. e., the scale is 100 : 1. [Illustration: Fig. 51. Permanent chart quadrat, _Andosacile_, _Carex-Campanulacoryphium_.] [Illustration: Fig. 52. Chart of the quadrat shown in figure 51. Legend: a, _Androsace chamaejasme_; c, _Carex rupestris_; t, _Tetraneuris lanata_; p, _Potentilla rubricaulis_; as, _Arenaria sajanensis_; ar, _Artemisia scopulorum_; ag, _Agropyrum scribneri_; sa, _Silene acaulis_; st, _Sieversia turbinata_; d, _Dasyphora fruticosa_; al, _Allium reticulatum_; o, _Oreoxis alpina_.] =209. Mapping= is invariably begun at the upper left-hand corner of the chart, and is carried across the strip marked off by the plotting tape, decimeter by decimeter. As soon as this strip is completed, a second one is formed by moving the top tape to a position one decimeter below the plotting tape, which then becomes the upper one. This is repeated until the last strip is reached. Little difficulty is experienced in locating each plant exactly, as the decimeter interval is small, and the centimeter square which corresponds is divided into twenty-five tiny squares. Each plant is put in whenever possible, but mats, turfs, and mosses are merely outlined in mass if the individuals are not distinguishable. This holds true of all large rosettes and mats, even when they are single plants. Symbols were formerly used for indicating the various species. They have the advantage of requiring little space on the chart, and the disadvantage of necessitating constant reference to the legend. They are at present replaced by initials. By this plan, the decapitalized first letter of the generic name is used if no other genus found in the quadrat begins with the same letter. If, however, two or more genera begin with _a_, for example _Agropyrum_, _Anemone_, and _Allium_, the most abundant one is indicated by _a_, and the others by the first two letters, as _an_, _al_. In case two species of the same genus are present, the species initial is used in connection with that for the genus, as _ac_ and _ar_ for _Agropyrum caninum_ and _Agropyrum richardsonii_ respectively.