204 PLANT PHYSIOLOGY AND ECOLOGY 



the sake of convenience, larger quadrats are square also. A 

 major quadrat is a square of four units, and a perquadrat one of 

 sixteen units, i.e., it is four meters square. Quadrats are also 

 named with respect to the use made of them. A list quadrat is 

 one in which the species are listed, and the number of individuals 

 of each is counted. Chart quadrats are those in which the position 

 of each plant is accurately indicated upon the chart of plotting 

 paper. Permanent quadrats may be of either sort, though they 

 are nearly always charted. They are distinguished by the fact 

 that they are marked in a way to permit of study from year to 

 year. The denuded quadrat is a permanent one, from which the 

 plants have been removed in order that the manner in which they 

 re-enter may be followed. 



218. Marking out quadrats. The tapes used in establishing 

 quadrats are one or two meters long and a centimeter wide. 

 They are divided into decimeter intervals by means of eyelets, 

 and the intervals are numbered from left to right as conspicuously 

 as possible. The tapes are held in position by means of wire stakes 

 which hold the tape close to the ground, and have loops by which 

 they are readily moved. 



In staking a quadrat the end tapes are always placed so that 

 the numbers read from left to right, and the side tapes so that 

 they read downward. In making a chart a fifth tape is stretched 

 parallel to the top tape and a decimeter from it. When this 

 strip is charted, the upper tape is moved to the next interval, and 

 so on, thus permitting the rapid and accurate mapping of the 

 whole quadrat. In all cases care must be taken to stake quadrats 

 in such a way that they are square. 



219. The list quadrat. This is used when it is desired merely 

 to obtain the number of individuals, i.e., abundance, usually in 

 connection with the chart quadrat. The size of the list quadrat 

 depends chiefly upon the nature of the vegetation. In herbaceous 

 formations the usual size is the major quadrat which is two meters 

 square, but when the plants are small and crowded the meter 

 quadrat is used. 



In listing a quadrat, i.e., counting the number of individuals 

 of each species, the smaller, less conspicuous plants are listed first, 

 since these are apt to be tramped down. When the outside 

 tapes and the taller species afford sufficient landmarks, a single 

 species is counted at a time. Otherwise a fifth tape is used to 



