POTASH FROM KELP. 11 
shore kelp of which two species, Laminaria farlowii and Eisenia 
arborea, also have corrugated leaf blades. 
Young plants 3 or 4 feet long were found in some number on the 
beach at La Jolla in November, 1917. One or two small plants were 
found among these. Again, in February, 1918, a very few small 
_ plants were found, of which two were undivided. In July, 1918, 
_ young plants from 1 to 12 feet long came in, in numbers comparable 
- to the smaller plants found in May, 1919. It would thus seem from 
these observations that young plants may be found at nearly any 
time of the year, but in abundance only from late spring to mid- 
summer. Plants brought in by storms in winter or early spring 
usually have large fronds and well-developed holdfasts a foot or 
more in diameter. Of the other plants, the holdfasts are commonly 
_ dead in the center, some having only a shell of living hapteres 
around the outside. The center begins to die, apparently, in the 
second year, so that these plants are more 
than a year old. Some of the largest may 
be 5 years old or older. The comparatively 
smal] number of plants that come in on the 
beaches certainly indicates a smaller amount 
of renewal than occurs in a bed of annual 
kelp. It is not possible, though, to make any 
near estimate of the age attained. Most 
plants are probably destroyed by being torn 
from their anchorage and carried ashore. 
STAGES OF DEVELOPMENT. 
The stages in the development of the plant, _ 
after it has become of sufficient size to be (8s) 
= . : : Ly 
seen without the microscope, may be rather 
hastily sketched, since Skottsberg (5)* has de- 
scribed them in detail. In the earliest stages ("Ga qakONS Ray Shen 
thus found, the plant has a single leaf with a 6 priaty See 
broadly rounded base (fig. 3), a distinct stipe, pnickiry Splits visible at 
and a conical holdfast. As it grows, hapteres tie aan ee 
bud out in whorls above the original holdfast. 
The increase in the length and the diameter of hapteres is very 
rapid at first. The stipe enlarges upward as successive whorls of 
hapteres are given off. The intervals between the first few whorls 
are so short, and the increase in length of successive hapteres so 
rapid, that the holdfast of a young plant becomes very flat. When 
a rapidly growing plant has attained a height of 4 or 5 inches, the 
first longitudinal split begins to develop at the base of the leaf- 
blade. A vigorous plant may have a height of nearly 2 feet before 
the right and left halves of the primary blade are fully separated. 
By the time the first split has attained a length of 1 inch, the 
secondary splits begin to occur. In contradiction to what Skotts- 
berg (&) states, the first splitting usually separates a symmetrical 
blade into equal divisions. The secondary splits separate the first 
two leaves into unequal parts, of which the outer or marginal two 
are larger than the inner or central pair. The margins begin to 
1 Figures in italics in parentheses refer to literature cited at the end of this bulletin. 
