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TOO University of California Publications in Botany [Vol. 8
wider, slightly ovate, truncate, growing point very slightly depressed,
midrib moderately prominent, cryptostomata absent or very sparse;
receptacles yellowish, complanate when young, frequently becoming
tumid at maturity, hi- tri-furcate, 4-7 cm., rarely 10 cm. long;
conceptacles large.
fornia.
Growing on boulders and rock ledges. San Francisco Bay, Cali-
Gardner, Genus Fucus, 1922, p. 26, pis. 18, 19.
This relatively small group of Fucus plants, although very much
circumscribed in its distribution, seems so distinctly marked off in its
combination of characters from other species, particularly from those
in the southern portion of our range, that it is worthy of specific rank.
The combination of characters that distinguish this species consists
of the following :
relatively long and narrow, smooth and glossy fronds,
strict, even overlapping habit of the terminal and subterminal seg-
ments, the dark brown color with yellowish receptacles at maturity,
absence of caecostomata, and the cryptostomata, when present, incon-
spicuous. Its affinities with F. edentatus may possibly be traced, but
they seem too remote to merit much serious consideration.
66. Pelvetia Dec'ne and Thur.
Fronds of tough, firm consistency, flexuose, the whole plant when
young, and the young terminal growing parts considerably flattened,
without midrib, becoming more or less terete with age, especially
toward the base, arising from a solid, disk-shaped holdfast ; growing
region apical ; branching dichotomous, usually abundant ; reproductive
organs, antheridia and oogonia, developed in conceptacles limited to
the terminal, metamorphosed parts of the branches, the receptacles;
oogonia developing two viable gametes, or eggs ; monoecious.
Decaisne and Thuret, Rech. sur Antherid., 1845, p. 12.
This genus was founded on the Fucus canaliculaius of Linnaeus
(Syst. Nat. II, 1759, p. 716) based largely upon the fact that the
oogonium produces but two viable eggs instead of eight, the character-
istic number for the genus Fucus. Eight nuclei are formed in the
oogonium, but six of them are extruded between the two eggs at the
time of their formation and become functionless. The eggs are
fertilized outside of the oogonia as in the genus Fucus.