66 Pub. Puget Sound Biol. Sta. Vol. 2, No. 35 



impossible to count them. Often individuals only 6 or 7 years old are 

 found on which some of the leaf-traces are no longer discernible. But 

 some individuals show the marks with a dependable degree of certainty. 



If the plant grew roughly the same number of leaves per year after 

 the first year, one could count the years back along the stem by the 

 leaf-traces, perhaps adding one for a first year with only 1 blade. Just 

 how old the plants are when the first lateral leaves appear is uncertain. 

 However, on the first of August there was still quite an abundant crop 

 of small plants without lateral leaves, altho a few showed signs of them 

 (Figs. 3 and 4, b). Table 1 gives, the results of observations made in 

 the manner described. 



Table 1. Shoicing number of rings, and the estimated age btj the 

 number of leaves and leaf-traces. 



Leaf-traces and Estimated age bv Rings 



Leaves ^ , ^ f ' 



Leaves number oi leaves at 25 mm. 



20 230 13+ 13 



11 84 10— 8 



18 81 6+ 6 



13 72 8 — 6 



13 117 11 11 



17 142 10+ n 



11 40 6— 5 



Thus the age figured by the leaves and leaf-traces roughly cor- 

 responds with the number of rings at 25 mm. from the base. 



The number of rings figured from the leaves is more on the average 

 than the number of rings counted. This may arise: (a) Thru indistinct 

 rings; some might have been missed in the counting. (b) Thru the 

 number of leaves not being constant; in fact it is not likely that the 

 number of leaves per year is constant. (c) Thru the counting of the 

 leaves in July, when probably not all had yet been formed. The frac- 

 tional years figured and shown as + or — in table 1, are well within the 

 limit of possible error, and are likely due largely to variation in the num- 

 ber of leaves annually formed. The number of rings corresponds closely 

 enough with the age figured by the number of leaves, to suggest that the 

 rings are annual ones like those of trees, and not successive during 1 

 year, like those of beets. The evidence is not conclusive, however. 



Further, cross sections through the upper part of the stalk show that 

 there is only 1 ring among the lateral leaves of the current year. The 

 second growth ring begins very near the point between the upper old 

 lateral leaves and the lower new lateral ones. The faintness of the 

 rings makes the exact spot difficult to determine. A longitudinal section 



