least at Port Renfrew, it seems probable that their production is a seasonal phenomenon taking place only for a limited period before the fruiting season. However they are formed, they do not reach their full size at first. The youngest are always shorter and narrower than the older and entirely lack the characteristic base. Some of the smallest remind one of the young sporophylls of Pterygophora and have the appearance of being outgrowths from the meristem as in that species, but the writer does not feel sure that they are normal. Further information on the origin of the sporophylls will be very welcome because of its importance in determining the relationships of this plant to the other genera of kelps.

At length, by branching and production of sporophylls a plant is formed with several hundred laminæ, in extreme cases reaching lengths of a meter, while the whole plant is often two meters long. The stipe at the base becomes 10-20 cm. in thickness and is marked with many annual rings of growth. The holdfast clings so tenaciously to the rocks that it will support a man's weight. On a flat bottom the plants stand upright, but they hang down when growing on an overhanging cliff, as in the photograph (Fig. 27). As in all water plants, their only way of maintaining themselves in the strong currents in which they live is by bending before them. Accordingly, rigidity is developed only in very large basal portions of the stipe, while the terminal branches have not sufficient stiffness to support the plant when out of the water. Lessoniopsis thrives only in places where the surf is very heavy and is there found along with Postelsia, the sea palm, the most typical of all the cumaphytes, but it does not withstand drying so well as that plant and consequently grows at a considerably lower level.

C. Egregia

To one acquainted with the kelps only through the more widely distributed genera such as Laminaria and Alaria, Egregia must always be the most interesting of the family. Algologists agree in assigning to this plant the high

FIG. 27. Lessoniopsis (hanging) and Postelsia (upright) growing on an overhanging shelf exposed to the heaviest surf. Lessoniopsis is about two meters long and Postelsia, one half meter.

est place among the kelps as being the most specialized of them all. It is a genus of the western coast, represented by two species, one northern, the other southern. Both are extremely variable and in their many forms and intergradations present to the taxonomist a problem of more than usual difficulty. Some features of the morphology of the northern species, Egregia menziesii, have been presented in a paper by Ramaley ('03), illustrated with some excellent figures of adult and middle-aged plants, while Reinke ('03) has also given figures and a brief description of somewhat younger plants. The development of this species which grows abundantly at the Minnesota Seaside Station, will be worth considering in detail in connection with the other kelps discussed above because of its greater complexity.

Egregia, like Nereocystis, has an extremely long stipe; indeed, in proportion to its lamina its stipe is much longer, but its character is totally different from that of Nereocystis. In the latter plant the stipe stretches from the holdfast, frequently attached to a depth of twenty or

thirty feet, like an anchor rope, to the surface, where it holds the large float and laminæ against the impact of the heavy surf. This stipe is often less than one centimeter in thickness for half its length, but of such surprising strength that the native fishermen tie their boats to these ready-made anchors and ride out a storm, as noted by MacMillan ('99). The stipe of Egregia, however, while slender and flexible, is not bare, but covered with very numerous short proliferations along its whole length giving it the appearance of a feather boa. Some of these are photosynthetic areas, some sporophylls, some floats filled with air. The presence of such organs as air vesicles so near the holdfast shows clearly the plant's adaptation to a shallow-water habitat. It grows attached to rocks which are never deeply submerged and are uncovered even by a moderately low tide, where its branches, buoyed up by their innumerable pneumatocysts, float with their whole lengths on the surface of the water. To the boatmen along that shore a thick bed of Nereocystis is a sure sign of deep water, but a bunch of Egregia as surely marks a rock to be avoided.

The youngest plants of Egregia are extremely difficult to separate from those of Hedophyllum. The juvenile forms of both these kelps are dark brown, distinguished from most others of their size by shorter stipes, together with a rather strong development of hapteres. The youngest plant of Egregia found (Fig. 28) was 25 mm. long, with a lamina about 20 mm. long and 10 mm. wide. The holdfast had already developed a circle of secondary hapteres, although the primitive holdfast could be made out beneath the secondary. The stipe was but 3 mm. long, cylindrical, and featureless except for a very slight thickening about a millimeter below the base of the blade. This appeared to be the beginning of the proliferations which characterize the later stages of the plant.

The thickening of the stipe soon becomes more pronounced and develops into a pair of horns about a millimeter long just below the base of the lamina and lying in the same plane (Fig. 29). These are the only dis

FIGS. 28-31.
FIG. 28.

Egregia.

Youngest plant, barely distinguishable from Hedophyllum at this

age, cf. Fig. 37, which is less eroded.

FIG. 29.

Plant showing the first pair of proliferations on the stipe. FIG. 30. Plant with the transition region roughened by many capillary proliferations, tuberculate ridges appearing in the base of the lamina.

FIG. 31. Base of a much older plant showing the differentiation of the first branch (b) made evident by the appearance of proliferations on its stipe, first pneumatocyst (p) just appearing, base of stipe remaining smooth.

FIGS. 32-34. Egregia. One half natural size.

FIG. 32. Whole of the plant shown in Fig. 31, proliferations on the lamina absent at the tip, but well developed below.

FIG. 33. Much younger plant than Fig. 32, capillary proliferations prominent in the transition region, laminar proliferations just beginning to appear on margin of both stipe and lamina, tip of lamina smooth, other portions covered with protective ridges.

FIG. 34. Older plant in which the lamina has reached its maximum development and the stipe has begun to grow, several well-developed pneumatocysts and young branches are evident among the outgrowths from the stipe.

tinguishing features of the plant until it reaches a length of about 40 mm. In plants of about this length a few round tubercles begin to appear at the base of the lamina, which has hitherto been smooth as in Hedophyllum. A specimen 75 mm. long (Fig. 30) showed numerous tubercles in the transition region, giving it a roughened appearance; and there were three instead of two horns below the zone of the tubercles. The basal portion of the stipe was still smooth as in the youngest specimen. In this plant the stipe had elongated scarcely at all and the growth had been restricted to the lamina, which extended through 70 of the 75 mm. of the plant's length. Tubercles similar to those of the transition region had also appeared and these were shown by transmitted light to be connected with streaks of denser tissue running lengthwise through the lamina.

After this stage, as in Lessoniopsis there is some variation in the age at which the various structures appear. A specimen 18 cm. long (Fig. 33) will serve as an illustration of the next step. Here the streaks beneath the tubercles of the lamina had become prominent ridges, much larger than the small tubercles at their summits. The ridges stood out so strongly as to cause depressions on the opposite side of the lamina beneath them. This gave the lamina a wrinked appearance and added greatly to its strength. The margin was entire or slightly undulate, but at the base were a few short serrations which looked much like the tubercles of the stipe. The roughened region of the stipe was about 1 cm. in length and no longer terete like the lower smooth portion, but somewhat flattened. In place of the horns of the younger specimens were several outgrowths, the largest of which bore a small orbicular lamina. The holdfast had become nearly 2 cm. in diameter by the great elongation of a few hapteres.

In view of the proportions assumed by the adult plant the relation between the lamina and stipe in the juvenile forms is most interesting. In the smallest specimen the lamina is only about three times as long as the stipe.