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688 University of California Publications in Botany [ VoL - 8
receptacles definitely delimited, complanate to moderately tumid,
decompositely furcate, mostly spreading and acuminate, 3-4.5 em.
long; conceptacles numerous, conspicuous.
Growing on boulders, logs, etc., in the lower littoral belt. Sack-
man's Point, near Tracyton, Kitsap County, Washington.
Gardner, Genus Fucus, 1922, p. 49, pi. 53. Fucus evanescens,
Tilden, Amer. Alg. (Exsicc), no. 235.
Tilden's no. 235 seems to belong here, although the specimen in
Setchell's copy of her American Algae is only a fragment and just
beginning to produce receptacles.
The distinguishing character of this form is the decompositely
furcate receptacles, often widely divergent. As many as eight diver-
gent apices have been observed with a common base. The fronds are
decidedly flaccid and dissolve rather readily in fresh water after
being dried.
7. Fucus evanescens f. intermedius Gardner
Fronds foliaceous, flaccid, 12-18 cm. high, light brown to yellowish,
dark brown on drying, holdfast and stipe small, angles broad, rounded
segments linear, reduced above each forking, 1-2 cm. wide, crypto-
stomata 15-25 per sq. cm., midrib narrow, prominent, percurrent, alae
relatively wide, membranaceous; receptacles broad at the base, 1-2-
furcate, acuminate or acute, complanate or tumid with mucilage,
definitely delimited; conceptacles small, numerous.
Growing on rocks in the middle of the littoral belt. East Sound,
Orcas Island, Washington.
Gardner, Genus Fucus, 1922, p. 44, pi. 44.
This form seems unmistakably connected, through its narrow
specimens, with F. evanescens f. costatus on one side, and, on the other
side, through its widest specimens, it seems not imlike certain narrow
specimens of F. evanescens f. pergrandis. It differs from the former
in having wider segments not perceptibly reduced in width, as in
f .
costatus, above the forkings, and in having wider, much more robust
and blunt receptacles. From the latter it differs in being much less
robust throughout, in having fewer cryptostomata, and in having much
more delicate and membranaceous alae.
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