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1925] SetcheU-Gardner: Melanophyceae 631
Leman (lac. cit.) was the first to publish a critical diagnosis of
the species under the combination, Laminaria porra. Nothing was
done with it in a botanical way until 1876, when Areschoug redescribed
it from material collected by Dr. G. Eisen, at Santa Catalina, Cali-
fornia, placing it with Nereocystis as N. gigantea. Later (1881) he
created the genus Pehigophycus to receive the same species where it
remained until the combination employed here was made (cf. Setchell,
loc. cit.).
tribe 3. LESSONIOPSEAE setchell
Members of the Lessoniaceae having specialized sporophylls arising
as outgrowths on the outer margins of the transition place where
splitting is about to occur.
Setchell, Kelps of the U. S. and Alaska, 1912a, p. 160.
The tribe of the Lessoniopseae might perhaps be placed with equal
propriety either under Lessoniaceae or under Alariaceae, since the
sole genus, monotypic, has the characters of each of these families.
The plant, however, has the habit of a Lessonia and this influences us
strongly to place it nearer to Lessonia than to Alaria.
54. Lessoniopsis Reinke
Frond differentiated into holdfast, stipe, blade, and sporophylls;
holdfast consists of a dense mass of short, thick, dichotomously
branched hapteres; stipe short, cartilaginous, very dense and rigid,
arborescent, more or less deeply furrowed, merging into hapteres below,
irregular in outline, profusely dichotomously branched above, branch-
ing taking place by splitting in the meristematic region, terminating
in long narrowly linear blades with distinct percurrent midrib and
stipitate base ; the meristematic transition region at the base of each
blade giving rise to sporophylls in pairs, 1-3 pairs each season.
Reinke, Studien zur Entwick. Lam., 1903, pp. 25-28.
Lessoniopsis is one of the many monotypic genera of kelps thus
far known exclusively on the west coast of North America. It was
established by Reinke to receive Lessonia Hit oralis Farlow and
Setchell. Although among the relatively recent discoveries, its morph-
ology, anatomy and life-history, except as to the embryonal stages,
have been quite thoroughly made known.
In its method of development of the sporophylls, its affinities are
close to Pterygoplwra. It resembles Lessonia in its method of dicho-
tomous branching of the blade and the consequent production of new
blades.