8 BULLETIN 1191, U. S. DEPARTMENT OF AGRICULTURE. 
minating not earlier than the previous November and probably not 
before December or January. Thus a young plant attains a height 
of 18 inches in the first six months of its life. Very probably under 
the more favorable conditions of the kelp beds young plants attain 
a height of from 10 to 15 feet or more in the first six months. 
The young plants that had measured 18 inches in height in Feb- 
ruary had changed so much by the early part of May as to be 
scarcely recognizable. One not far beyond the end of the first sec- 
tion of the breakwater may be cited as an example. In the middle 
of February this plant was about 18 inches high, with a slender 
primary stipe and its first two fronds only well started, a few 
cysts forming, and the whole plant delicate in appearance. In pre- 
vious monthly visits, the plant had not been distinguished from the 
young plants 1 to 6 inches high of the single-bladed kelp, Laminaria 
farlowtwi, among which it grew. Early in May, less than three months 
after the plant had been noted as a young plant, with a height of 
18 inches, it had a stout primary stipe and main branches, two fronds 
5 or 6 feet long—very nearly the length usually attained by plants 
growing in tide water—with stipes, cysts, and leaf-blades of average 
size, and 6 additional fronds well started. A considerable number 
of long, narrow leaves were clustered at the base as in large plants, 
and on one of these a small sorus was found. When examined under 
a microscope this sorus was found to have geod spore cases, on both 
sides of the leaf, containing nearly matured spores. 
The primary stipe, or “ trunk,” it may be called, had become stout— 
over one-half inch in diameter—with a flat holdfast at the base, 
about 4 inches in diameter, hardly large enough to anchor the plant 
securely. Six additional whorls of stout hapteres or “ roots” were 
growing out from the stipe above the holdfast. When visited again 
at the end of the month, the plant had nine good fronds, of which the 
first two were in the sloughing stage. No fruit was seen, probably 
because there is a great decline in fruitage in May. All the young 
hapteres noted the first of the month had grown down and attached 
themselves to the rock, so that the plant now had a good, stout hold- 
fast, of the conical or dome-shaped type characteristic of large 
kelp plants of various species. The primary stipe was now starting 
out from the underside of one of the larger branches. 
Working backward from this plant, it may be stated that from 
the time a young plant has begun to send up its first fronds, not 
more than four months elapse, if conditions are favorable, until it 
has produced a clump of fronds of average weight. Then, since 
plants germinating from the spore in December are sending up their 
first fronds in May, we can safely say that plants germinating at 
a time favorable for most rapid development may be producing kelp 
in commercial quantities in 10 months or less. It is necessary to 
use the expression, “a time favorable for most rapid development,” 
because, thus far, only spores germinated in early winter have 
been found to produce rapidly developing plants. Spores germinat- 
ing even as early as February, when the water is at its lowest tem- 
perature, produce sporelings which, while they take on a healthy 
color, seem to keep their original size for months. 
Kelp beds torn out by storms in late winter or early spring do 
not come back until the second season. This discrepancy between — 
the rate of regeneration of beds destroyed by winter or spring storms ~ 
