14 BULLETIN 1191, U. S. DEPARTMENT OF AGRICULTURE. 
only very sparingly, fruitage increasing with age. While the first. 
fronds are growing up and additional fronds and growing points are 
arising, there is an increase in size in all parts of the plant. By 
the time the fronds have attained the surface of the water they are 
producing stipes, cysts, and leaves of nearly normal weight. The 
basal leaves are as large as those of an old plant. The primary stipe, 
less than one-eighth inch in diameter ina plant 6 months old, s sending 
up its first fronds, attains a diameter of one-half inch by the time 
the plant is 9 or 10 months old. As the foliage of the plant | becomes 
heavy and the waves threaten to tear it loose from its anchorage, 
eavitiGadl hapteres bud out in three or four whorls at a time. 
Branching repeatedly, they soon form a dense tangle. These later 
hapteres are much stouter than those comprising the holdfast of a 
small plant. The whorls come out at intervals of nearly half an 
inch. They are produced in such numbers that they soon conceal 
the primary stipe. Additional hapteres grow down from the 
branches until an old plant has all the older portions of its lower 
stems hidden in a huge conical holdfast, sometimes 3 or 4 feet in- 
diameter and more than a foot high. The 
older hapteres, as well as the portions of 
stem that bore them, die and decay, so that 
an old clump has a number of stems bear- 
ing fronds and hapteres. It thus becomes 
impossible to determine whether a large 
clump has been derived from one original 
plant or from several. About the time 
branches begin to send down hapteres, the 
plants begin to show the differences which 
separate them into the second and third 
groups. 
Fic. 6.—Small upper part of | In the second group the shrubby lower 
stipe, showing ordinary stems ascend more or less steeply from the 
base. They grow upward much more rapidly 
than successive whorls of hapteres ‘ascend them, thereby attaining a 
height of a foot or more above the top of the holdfast. Because of 
rather slow growth and ascending habit, the group of stems or axes 
remains centrally located, and the larger the holdfast becomes the 
longer the hapteres have ‘to be to take hold around the outer edge. 
The increasing difficulty of producing hapteres of sufficient length 
to secure it to its anchorage is one of the factors determining the 
length of life attained by the plant. This is the typical Macrocystis 
pyrifera, with the typical pear-shaped cysts, hollow nearly to the 
base—the most abundant deep-water type on the southern California 
coast. 
It is often greatly modified by environment. In the more exposed 
beds of the islands, the stipes are very stout, the cysts long and 
tapering, with thick walls, and the blades long, narrow, and very 
thick. The plants are tough in texture, and rich chestnut brown in 
color. In the quiet water “of the more sheltered island harbors the 
plants have slender stipes, nearly globular thin-walled cysts, and 
very broad, thin leaves, sometimes more or less heart-shaped at the 
base. The color of the whole plant is pale yellowish brown, and 
its leaves are very fragile. Along the mainland the plants are inter- 
