Reproduction. 



81 



Hence we may conclude that the weight gained in four years' growth 

 can scarcely exceed i ounce, and probably seldom amounts to that. 



The following are measurements (in millimeters) from rapidly grow- 

 ing plants from Station 2, collected in January, 1908: 



TABLE 34. 



It is of interest that plant 4, though a slower grower in height than 

 i, made weight about twice as fast. This is due to the larger number 

 of twigs. Plant 4 may be regarded as an expression of the best results 

 which may be expected in this station. We may therefore conclude that 

 the weight of 4-year-old plants will not on the whole exceed 1 5 grams or 

 0.5 ounce, and that the maximum weight for a 6-year plant will not 

 exceed, say, 45 grams or 1.5 ounces. 



RATE OF GROWTH IN MEDIUM-SIZED PLANTS. 



As in the case of seedlings, the annual accretions of growth have 

 been measured only when sufficiently clear for certain recognition. The 

 last 2 to 5 or more years' growth was measured, according to the visi- 

 bility of the markings. Several hundred measurements were made in 

 all, of which the summaries and averages alone are given in table 35. 



TABLE 35. Average amount of growth per year in the localities indicated. 



1 NOTE. The plants in this locality showed very rapid growth in 1906, explainable by the rain and 

 by their having been previously cropped back. The branches were few in number, so that the plants, 

 though relatively tall, were very light in weight. This figure would therefore better be thrown out of 

 account, in which case the average falls to 38 mm. per year. The datum for Station 2 has been checked 

 up by a later count, 26 measurements giving an average of 32 mm., and at this point it may be said 

 that the data above given are collated from measurements made at different times, results being used 

 as checks, the one on the other. 



