- 406 BOTANICAL GAZETTE [DECEMBER 
The ribbed surface of the trunk is due to successive crowns, and 
affords some basis for an estimate of the age of the plant, but in the 
lower part of the trunk of tall specimens the ribs may become too 
obscure for accurate counting. The scars of the individual leaves, 
which are so distinct in D. edule, are so obscure in D. spinulosum that 
counting in the lower portion of large trunks is out of the question. 
Whether the duration of the crown is two years, as in D. edule, I was 
not able to determine, but assuming the duration to be two years, 
the tallest specimens might not be more than 4oo years old. How- 
ever, any estimate can be little more than a guess, until the duration 
of crowns, and the effect of scale leaves, cones, and resting periods 
upon the growth of the trunk have been studied much more carefully. 
Still, I am inclined to believe that a 10™ specimen is no older than a 
1™ specimen of D. edule. 
At the base the trunk is much enlarged, often having twice as great 
a diameter as it has o.5™ higher up. The roots are often exposed 
for considerable distances, especially in precipitous places, where a 
root may hang down along the surface of the rock. One root hanging 
down in this way was exposed for a distance of more than 12™ and 
was 5°™ in diameter where it again entered the soil. 
Cutting through the trunk, which is not nearly so hard as that of 
D. edule, it is seen that there is a single zone of wood surrounding the 
large pith. The origin and development of the vascular cylinder, as 
seen in embryos and young seedlings, is being studied by HELEN A. 
Dorety. 
Both EICHLER and Dyer gave accurate descriptions of the leaves 
as they appear on small plants. E1cHter’s largest leaf (65° in 
length) had 38 pinnae, the lowest of which were rudimentary. DvyER’S 
leaf was about 1™ long, with 70 pinnae on each side. On plants 2™ 
or more in height the leaves reach their full size, so that leaves 2" 
long, with 100 leaflets on each side, are not uncommon, while one leaf 
measured 2.2™ in length and had 117 leaflets on each side, the leaflets 
being 20°™ long and 1o™™ wide. There is great variation in the 
leaflets, some only 14-15°™ long being 15™™ wide. ‘There are 5-8 
sharp spines on each margin of the leaflets of large leaves. The 
lower leaflets become more and more reduced, until the lowest ones 
are nothing but spines, so that the leaf bears considerable resemblance 
