Reproduction. 



71 



obvious that in the last station reproduction by seedlings is relatively very 

 good, especially as the counts were made at the close of a long drought. 

 A condition such as this might, in the light of table 25, be expected to 

 lead to a good stand of guayule. From a consideration of the curves 

 based upon table 2 5 , some further points of interest are discovered. There 

 is a large falling off in numbers of plants between the average weight 

 of about 4 and 1 2 ounces. This, as seen in the curves on pages 87 and 88 , 

 is the period, approximately, of maximum rate of growth, viz, between 

 8 to 10 and 13 to 15 years of age, during which time there is a loss of 

 total weight of about one-fourth to one-third, as nearly as we may calcu- 

 late. From the nature of the conditions, many of which are undetermi- 

 nable, such calculations can be only loosely approximate, but it can hardly 

 be doubted that, if the rate of reproduction by seed from plants, say 

 from 6 to 8 ounces in weight, can be depended upon quantitatively as 



0-%. y z -\ "-2 2-3 3-4- 4- 



POUNOS 



FIG. 12. The relative numbers of various-sized plants on different quadrats. The numbers 

 at the ends of curves refer to the tables corresponding. 



indicated in the table under consideration, it is an economic loss to allow 

 plants larger than these to remain. From this point of view alone it 

 may not pay to allow the plants to remain after the age indicated by 

 the weight of 6 to 8 ounces has been attained, as the numbers which die off 

 are great enough to cause a considerable falling off of total weight. 



The data show also that the initial monetary return from a harvest- 

 ing of guayule may be as great or greater from a stand of a few large 

 individuals, but the areas with large numbers of smaller plants give 

 promise of future returns. 



An important desideratum is to determine how to improve these 

 conditions. Here, let us say, is a good field of guayule, as regards first 

 returns. The bulk of the weight is in large plants, and the small ones 

 are too few for a ready reseeding of the area after depletion. It is hardly 

 too much to say that vast areas are in this condition. What may be 



