New Pacific Coast Marine Algae I

50 Pages·2015·6.67 MB·English

UNIVERSITY OF' CALIFORN IA PUBLI CATIONS
IN
BOTANY
Vol. 6 , No. 14, pp. 377-41 6, plates 31-35 June 30, 1917
NEW PACIFIC COAST ALGAE I
~IARINE
BY
NATHANIEL LYON GARDNER
Arthrospir a maxima Setchell et Gardner sp. nov.
Plate 33, fig. 3
Natans, aeruginea, in algis aliis intermixta; trichomatibu.s 7-9p.
cliam., laxe et aperte spiralibu , 3-8 fiexubus compo iti , ±0-601-' cliam.,
anfractibus 70- OIL inter se distantibus, non torulosi ; celluli 5-71-'
longis, di sepimentis clistinctis; granulis numerosis, era sis, angulatis,
refringentibusque et in dis epimenti frequenter dense aggregatis;
cellula apicalibu rotundati , membrana leviter incrassatis.
Trichomes 7- 9/J- cliam., forming an open regular spiral of 3- turns
40-60,u diam., 70-80,u between the turns, slightly tapering at the ends;
cells 5-7, u long, not constricted, with numerous, coarse, angular, r e
fringent granule frequently crowded at the partitions; end walls of
the terminal cells rounded, slightly thickened; color verdigri .
Floating in abundance among other species of Cyanophyceae in
warm salt water. Key Route P ower-house, Oakland, California.
July, 1916.
The habitat of Arthrospira maxima is rather unu. ual. The alt
water is pumped from San Francisco Bay into a erie of pond. of
considerable size. It i. then pumped through the electric pow·er-hon e
for conden. ing . team; it there becomes heated to about 60° C, and
is then allowed to run out where it i cooled again to the temperature
of the air before being pumped back into the power-bou e. It thu
appears that the plant is subjected to the. e rather unu ual extremes
of heat seYeral time. a clay and yet thrive.
ahundantl~-.
The genus pirulina was el'tablisbcd 'l'urpin in 1 27 (Turpin,
h)'
1 27, p . 309) . H e did not mention the tran vrr. c cell wall.. The. e
cell walL are quite oh. cure in the small form. of the gt>nu., ancl this
fact lecl later algologi. ts to regard them a. nniccllular plant. . In
1 52, tizcnberger (1 52, p. 32) folmclecl the genu Arthrospira to
378 Universt:ty of California in Botany [VOL. 6
P~"blications
receive a spirally twisted filamentous form whose transverse cell walls
are plainly visible. Thus the only apparent morphological difference
between the two genera is the stated difference regarding the trans
verse walls. This distinction is made use of by Gomont (1892, pp.
95-96), by Forti (1907, p. 145), and by Kirchner (1900, p. 63) . By
vV.
employing methods of differential staining, Professor A. Setchell
and I have determined repeatedly that this distinction can no longer
maintain. 1'he small, tightly coiled forms are really multicellular,
and hence no fundamental difference exists between the two genera.
However, since the described species are few and there is not likely
to be a very large number of new species added in the future, and
since the forms thus far discovered fall rather naturally into two
groups, those very small tightly coiled species with obscure cross
walls, and those rather loosely but regularly coiled species with con
spicuous cross-walls, all of which are fairly well known, it seems wise,
for the sake of convenience, to retain both genera, and emend the
diagnosis of Spirulina. Certain species of Phorrnidium and OsciUa.
tor£a can scarcely be distinguished as to the principal generic char
acter, the presence or absence of a sheath. All species of Phorrnidi'll?n
are at times of active growth after formation of hormogonia without
a sheath, and some well-recognized species of Oscz:llatoria may, under
certain conditions, develop a sheath. I have observed this in 0.
sctncta. The two genera are thus not absolutely distinct, but for
convenience they are botb kept up. Again, some of the small species
of both genera have very obscure In this respect they
cl~oss-walls.
bear the same relation to the larger species with definite cross-walls
that Spintlina bears to Arthrospiraj but in neither nor
Phorrnidi~"m
Oscillatm·ia has this been considered sufficient to warrant generic
distinction. The genus At·th1··ospira would doubtless never have been
established if the real character of Sp·ind.ina had been known at the
time.
A very close relationship exists between Spintlina and Arthr·o
Sp1'ra) on one hand, and a group of species of Lyngbya on the other,
as regards the spirally twisting character. Moebius (1889, p. 312)
described a new genus from Brazil which he called Spirocoleus LageT
concerning which he say Diesc Alge, fiir welchc ich eine neue
he1:rni~·, <'
Gattung aufstellen mw::;s, steht zu Sp'ir·ttlina in demselben Verhbi.ltniss
wie Lyngbya Ag. zn Oscillaria, Bose., inclem die schraubenformig
gedrehten Faden mit cin er deutlichen Scheide versehen sind."
Gomont transferred 1\Ioebius' species to Lyngbya, and Forti (1907,
1917] Gardnu· : A'rw Pacific Coast Jiarinc ... llyar I :ri9
p. 2 7) retains it as but al o retains Moebius' Npirocolcus as a
Slt<.:lt
convenient subgenus or scdion of the g-t•nus Lynubya, into which he
a. ·embles, along with L. Laycrhci111 ii, six otlwr of small
~1weies
dimen ,ion. , all of -which arc more or less spirally twist eel Arth ro-
spira Hta.rima is not mw.:h unlike Ly11ybya spirulinoides Gomont,
differing generically in tht• absence of a s lwath. IIowt•ver, the slwat h
of L . spirulinoides i said to be inconspicuous. I n another instance
Forti (1907, p. 207 ) has r etained Raht•Hhorst 's form vagi nata with
Arthrospira.
"filis subdistincte Yaginatis'' a. belonging to the genus
Spirulina Turp. cm0nd.
'rrichomata multicellaria, cylinclrica, (;>vaginata, laxe aut dPnsP
. piralia :pi ram laxam aut clan. am efficientia; trichomati. apex vulgo
aequalis. ellula apicalis r otnndata, calyptra nulla; en<.loehroma homo
genea aut cum granuli. instructa.
Trichouw. multicellular, cylindrical, eYaginate, loosrly or tightly
coiled into a more or less r cgnlar spiral; apex of tricl10me usually not
tapering; terminal cell rounded, without calyptra; cdl contents homo
gcneou or granular.
Chlorochytrium Porphyrae 8etrhell et GanlnPr sp. noY.
Plate 32, fig. 6
Yiride; ccllulis sphcl'icis, -±0-60/-t diam., in gel ina exteriori hos
pitis ub superficies geminas positis; ehlorophoris singuli., prime
parYi" clemum per plun•s ramos racliaut<>s emittt>nt1·s augescentihu:
et fine pariE>tem cellularum tegentihn. : pyrenoiclr singulo. magno,
in chlorophora ad partem snperiorem Ct'llnlae posito ; parietibus C!'lln
larum 2-3/-t cliam., hyalin is, non laminatis; propag-atione sexuali a
gametibu. biciliatis, 3--!J-t diam., fusiformilms aut f1' 1'P sphericis, per
foram en ovatum in pari etc externo (gam etangii) evadcntibus; propa
ga tione ascxuali a zoo:poris ant a aki1wt ibn. ignota.
Cell . pherical, -±0-60/-t cliam., embrclclcd within the ho. t on hoth
sides; chromatophore singlP, at first small, con'l'ing tlw upper part
of the young plant, th en inerea ing· in siz0 s<'nding out . evercll
h~'
racliabng anus and finally covering tlw cl'1l wall; p)Tcnoid single,
large, en1hcdclrcl within the chromatophor0 toward the upper part
of the cdl; C<'ll wall 2-:3 diam., hyalin<', not laminatl'd; color gras -
1..c.
green; sexual r eproduction hy biciliate g-ametes. :3--Jp <limn., fusiform
to almost spht>rical, rsenping through the m·al OJWning in the outer
wall; asexual reprodnction h;\' zoosporrs and by akinctes unknown.
Growing completely c>mhedded within i.hr ouft'l' membranr of
Porpl!yra prrforata f. sryrrr;ata Netl'llrll ancl IIus, Lan cls End,
~an
Franci. co. California, ..April. 1916.
\\.hile collecting algar in the ahoYr-mcntioued lnl'alit)·, I notit·Pcl
groups of l)lcmts of Pvrph yra on rol'ks near hig-h-t itlP limit wh1l'h
" 'ere considerably chnnfcd and almost as grPcu a" thL' small
[ '!1•a
Cniversity of Califontia Publications in Botany [VOL. 6
gro\\"ing in the arne habitat. I su pected the color to be due to the
death of the plant on account of their exposed condition, but a
ca nal glance with a hand lens revealed the pre ence of myriads of
small pherical cells of an endophytic unicellular green alga. Material
was taken to the laboratory, sectioned and studied. It was found
that myriads of these plants in all stage of development were inhab
iting the thick gelatinous walls of the Pm·phy-ra cell.. I began at
once to ::;earch through th'e literature to determine first to what genus
it seemed most closely allied, and second to determine whether it had
previously been characterized specifically. rr he first task has proven
to be by no means a simple one. rrhe second one was fairly readily
decided. Nothing, so far as I have been ahl(' to determine, has yet
been discovered that is just like it. It seems certainly to belong to
the Protococcaceae, and seem mo. t closely related to the two genera
Chlo'rochytriwn Cohn and ChlOt·ocystis Rt•inhardt. The limits of
these two genera are not well defined, which makes it more or less
presumptuous on the part of any one who attempts to ally, with
much degree of certainty, a new . pecies with either. Recently West
(1916, p. 212) has gone so far as to reduce C'ltlorocystis, along with
three other genera of \Ville's group Enclosphacr cae to synonomy,
retaining Chlm·ochytriwn, it being the olde!:it, as sufficient to include
the other three, which were founded npon cl1aracters which in his
judgment arc of minor importance, not cardim1l cnought to be ranked
as generic. A brief resume of some of t he more important writings
concerning these two genera may be of some value at this juncture.
It is not intended to be complete by any means. l\1any other valuable
papers b<'aring on the subject have been 'rhe chief points
eon~ulted.
at variance between the two genera are, the method of formation of
''gametes'' and ''zoospores,'' the matter of their conjugation, the
number of their cilia, the shape of the chromatophore. and the num
lH'r of pyrrnoicls.
Chlorochytri is the older of the two genera, and w·as established
um
by Cohn in 1 72 (1 72, p. 87), ba.rd upon a form endophytic in the
fronds of Lrm na trisulca, which he namNl C. Lcmuae. H e says of
th<• zoo!:lpore formation : '' plasmate viric1P primum in segmenta
majora cliviso, dein secedente in zoosponts innumeras pyriformes
vi rides proccssihus tu extm; rmissas. '' 'rhis method of zoo
bu1osi~
spor e formation docs not conform to that occurring in the plant under
considcl'ation in Porphyra. Wright ( 1879, p. 355) published a n ew
species of Chlorocltytn·wn which he dcd icatr>cl to Professor Cohn.
1917] New Pacific Coast Marine Algae I 381
Ga~rdner :
The most essential differrnce, he says, between it and Cohn's C.
Lenmae is the production of two kinds of zoospores, each kind having
but a single cilium (concerning which he was very much in doubt),
and in the method of their formation, of which he says, ''On the cell
arriving at an adult stage the whole of the green protoplasmic con
tents divides into a number of from ten to thirty, nearly circular,
zoospores, which escape through the neck-shaped portion.'' H e was
not wholly satisfied tl1at the form should be placed in the genus
Chlm·ochyt1·ium as diagnosed by Cohn, but placed it there more or
less provisionally. One infers that these ''zoo pores'' escape singly,
and not . imultaneously within a gelatinous utricle in the manner
reported by later workers as occurring in the genus Chlm·ochytrium.
Kjellman (1 83, p. 320) described Chlorochytn.um 1:ncluswn
stating that it has a , ingle chromatophore covering the entire wall.
H e states that a large number of ''zoospores'' are produced, but did
not state the manner of their formation, the number of their cilia,
nor their method of escape. De Toni (1889, vol. 1, p. 635 ) in diag
nosing the genus says of the chromatophore '' discif orme, '' and of the
reproduction ''zoospores sexualia vel neutra, '' that these reproduc
tive bodies have two cilia and are formed by repeated cell division.
Wille (1 97, p. 65) diagnosed the genus as having a single parietal
chromatophore with many pyrcnoids, zoospores with four cilia, and
gametes, both reproductive bodies formed by successive cell clivi ion,
and that the gametes escape in a mass a membrane
~urroundecl b~~
in which they conjugate. H e did not add an)' new features to the
diagnosis in theNa chtriige which he published in 1911. The diagno is
given by Collins (1909, p . 146 ) is very similar to that of Wille, but
he states that each kind of reproductive body ha two cilia.
The genus ChloTOC.lJstis was e tablished by R einhardt in 1 5
based upon material collected near Odes a on the Black • ea, which
he con. idered to be the same a that found by '\Vright on the coa t
of Ireland upon which he founded his species Cltlorochytriwn Colznii.
Chlorocystis was publi. heel in Russian and 1 have not acces. to the
original paper, but I J1ave and have made traciDgs of the draw
s~:cn
ings. J11dging from the drawings and the reviews of Reinhardt ·s
text, as compared with the drawing. and description. of Wright, I
find myself in accord with West (1916, p. 212 ). It to me that
~ecms
the difference between Chlorochytriwn Lem nae. of Cohn and the two
collections of plants of V\rright and Reinhardt, a. suming that they
are the same species hardly ·warrant the e. tablishm<'nt of a new
382 Unive'rsity of Californ·ia P'l(,blicat1.ons in B otany [VOL. 6
genus ; that "\Vright 's species, though perhaps incompletely diagnosed,
should r emain in the genus Chlorochytrium of Cohn, as pointed out
by W est, and that Reinhardt 's species from the Black Sea should also
be placed in the same genus but given different specific rank, and re
named. I therefore propose the name ChlorochytriU?n R e·inhardh.i.
l\1oore (1900, p. 100) wrote concerning a plant found by him at Lynn,
Massachusetts, growing on Enteromorpha, which he reluctantly re
f en·ed to Chlorocystis Cohnii. The plant is well figured and care
fully described. If compared with that which seems now to be the
general concensus of latest opinions as to what ar e the most important
characters that should constitute the genus Chlorochytriurn, lVIoore 's
plant should be allied with that genus, but is unlike any described
species of the genus. I propose the name Chlorochytr-ium M ooreii for
the form. It has been distributed in Collins, Holden and Setchell,
Phycotheca B oreali-Arnericana (Exsicc. ), no. 565, as Chlorocystis
Cohnii (\Vright) Reinh.
There still remain several phases in the life-history of Chlorochy
tri'lint Porphyrae to be worked out. At the time of collecting the
plant, the host, Porphyra, was nearing the end of its life-history,
that is, the majority of the plants were in the fruiting condition.
There are, however, a few plants of this species to be found at all
seasons of the year, and the basal parts of the old plants r emain for
some time after the plant f ruits. Probably the endophytic C. P m·
phyrae remains in these older parts over the season unfavorable for
growth and infects the newer generations as they appear. rrhe plants
become complet ely embedded within the host and no tube is left
behind through which the gametes escape. There is but a single
chromatophore, at first covering only the posterior, outer part of the
cell. This incr eases in size, at times thrusting out projections some
times becoming a network but finally practically always covering the
cell wall. In this earlier stage it resembles the chromatophore figured
by Reinhardt, the principal charact er upon which he founded his
genus Chlorocyst·is. C. Porphyrae differs radically in the method
of gamet e formation from that described by Reinhardt in his account
of the Black Sea plant. The cell divides first into two equal parts,
then successively into four, eight, sixteen, etc., up to five hundred
or mor e, depending upon the size of the plant, which may be ex
ceedingly variable ; whereas in Reinhardt 's plant the ''zoospore''
formation is by free cell division.
Miss Whitting 's Chlorocystis Sarcophyci seems to follow the
1917] Gardner: New Pac·ific Coast :Marine Algae I 3 3
method outlined by Reinhardt in zoospore formation. She states,
however, that the cells at times divide into several large sections prior
to spore formation, bnt is unable to interpret the function of such
division. It may pas ibly be that these are the earlier . uccessive
divisions which usually result in spore or gamete formation, but
which for some reason have been arre ted in development. l\Ioorc 's
plant follows the same method as that of C. P m·ph y1·ae in the matter
of the formation of reproductive bodies. Wille and Moore report
''zoospores'' with four cilia. Concerning this point my observations
are incomplete with reference to C. Porphyrac. The reproductive
bodies formed in this species, so far as I have observed, are gametes.
'"fhey have two cilia. I have observed them in great abundance) and
have observed their conjugation. The gametes escape singly through
the surface aperture, instead of the entire mass intact within a utricle
as reported for certain species, e.g. that found by Moore.
There is but a single large pyrenoid in C. Pm·phyrae, agreeing in
this respect with C. lVIooreii and C. Reinhardti:i. Wille characterizes
the genus Chlorochyt?·i,urn as having many pyrenoids, but West looks
upon that character more as specific than as generic.
West (1916, p. 212) i, of the opinion that the shape of a chromato
phore can not ordinarily be considered of sufficient stability to be
used as a primary basis of generic distinction. I am inclined to agree
with him on this point. Both lVIoore and I have shown that in the
forms upon which we have worked the shape of the chromatophore
is extremely variable, at times pas essing radiating, flattened lobes,
only partly covering the cell wall, but usualJy at maturity covering
the entire wall.
The four genera which We t has merged into Chlo1·ochytrillln
Cohn ( '72) are Endosphae'ra Klebs (' 1), Scotinosphaera Klebs
(' 1), Chlorocystis Reinhardt (' 5), and tomatochytrium Cun
ningham ( '88). 'J:'hey all agree in being holophytic, unicellular,
spherical or nearly so, wholly or partially endophytic plants with
a single chromatophore, covering the wall more or les. completely
and containing one or more pyrenoids. Reprodnction is by· gametes
or by zoosphores or by both. The plant which l have eli. covered and
described above, growing in PorphyHc. pos esscs these characters and
I have consequently allied it with the genus Chloroclzytn·um in the
larger sense of West.
ChloTochytn'wn P orphyraC' differ principally from Chlorochy
lll ooreii in having on]y biciliate gametes, as far a kno"rn, in-
t?·i'um
3 -! Vniversity of California Publications in Botany [VoL. 6
tead of quadriciliate zoo pore. of two size , as stated by ·l\Ioore; in
being completely embedded within the ho. t, making entrance without
the formation of a tubelike projection characteri tic of C. 11l ooreii in
tho. e instance in which it partially embed. itself; and in size, being
40- 60JL diam. as compared with 16-26JL in C. JJi ooreii. It differs from
Chloroclzytrium R rinhardtii in size and in the hape of the chromato
phore; C. Reinlwrcltii differs from C. Colznii Wright in hape, size,
characters of chromatophore, and reprocluctiYe bodies.
Gayella constricta etchell et Gardner sp. noY.
Plate 33, fig . 3-9, and Plate 32, .fig. 5
Filamenti , atro-viridibu., nanis, fa culati , 1-4 mm. altis, ba i
1 -20JL, apice ad diam., cylindrico-clavatis, uncinatis, frequenter
175,~-t
intervallisque constrictis, basi parce ramosi ; cellulis discoideis,
10-15,~-t
cliam., primo et infero totaliter serie singulari, superne longitudinaliter
u
in glomerulis et in duobus aut multioribu planitiebus clivi et diam
etron filarn entorum augescentibu ; filamenti. plerumque cylindrici
longe ad basem attenuatis, apice crassi . imi ·, maturis pa im (glomeru
lis aliquibus cellularum non dividentibus) lC'nte constrictis; parietibu
cellularum hyalinis, non strato:i., transverRi. valde tenuibus; chloro
phora singula, celluJam totam fere occupantibu. ; pyreuoide obscura.
Filaments small, dark green, some""'"hat tufted, 1-:1: mm. high,
1 - 20JL diam. at the base, up to 175JL at the apex, cylindrical-clavate,
uncinate, con. tricted at frequent interval. , paringly branched at
the base; cells di k-shaped, 10-15JL diam., at first in a single serie
throughout, remaining so for some distance at the base, hnt dividing
in groups longitudinally in two or more p1ane. above, increasing the
diameter of the filament and pre. erving it. cylindrical form in general
though gradually becoming larger, the terminal group of cel1s having
the greatest diameter; at frequent interval groups of 2-6 cells remain
undivided vertically, giving a constricted appearance to the mature
plants; cell walls hyaline, homogeneous; cross-walls very thin;
chromatophore single, occup)·jng nearly the entire cell; pyrenoid
ob. cure.
Growing in dt>prr. ion. and crevice. in rock, above high-tide level,
kept moist by claRhing salt spray. Tomalr. P oint, at the mouth of
Tomales Bay, l\Iarin County, alifornia.
This plant "·as found growing on exposed rock in company with
a . 1wcies of Prrtsiolrt. It is a rather unusnal c0incidence that the only
other known srwc·irs of Gayclla, viz. G. polyrhiza, is al. o
frequentl~·
f ound a. sociatt·d with a spccit>s of Prasiola. T his has led to the belief
that Gay ella is mrre1y a :tagr in the life-history of Prasiola, and in
dN·d Bprge. (1902, p. -1 2) states that he has found the transition
l'll
stages between Oayrlla polyrhi:a and Prasiola crispa. Collin (1909,
•
1917] Ga rdner : New Pacific Coast 11larin.e Algae I 3 5
p. 222) has retained the two genera separate, however, tating that
it is difficult to e tablish eli -tinctions among Gayella, chizogo 11 i H m
and P rasiola.
I have had Ga.yella constricta under ob ervation for over eighteen
months, having the material of it and the accompanying Prasiola
growing in the laboratory for over eight month . In some areas on
the rock the two plants ar e intermingled, but in others they arc
entirely separate, and the two can be distinguished by size and color,
the Prasiola being larger and the Gayrlla much deeper green. There
has not yet appeared the slightest indications of a metamorpho is of
one into the other, though many new plants have started. The evi
dence thus far at hand is that the. e two forms should be kept as
distinct genera.
I have compared Gayella const't£cta with the material of Gayella
polyrhiza Rosenvinge, as distributed in Collins, H olden and Setchell,
Phycotheca Boreali-Am e'ricana, no. 914. This distribution, though
to a large degr ee comparatively young, seems to be quite typical,
agreeing very closely with the descriptions and figures by Rosenvinge
(1 93, pp. 936- 939) . It possesses abundance of rbizoids, which in
this instance are mere prolongations of single cells remaining undi
vided. G. consttticta differs from G. polyrhiza in having fevver
rhizoids and these u ually much longer and mnlticellular; in having
deep constrictions in the mature filaments caused failure of certain
b~T
cells to divide vertically; and in the filaments being· uncinate.
Myelophycus intestinalis f . tenuis Setchell et Gardner forma noY.
Caespito us, incon picue tortus, 1.5-2.5 em. altus, 0.25- 0.75 mm.
cliam.; . porangii. unilocnlaribus late ellipticis, .J:0---±5,u longi , 30-35,u
latis; singulis aliis ut in specie.
Plants caespito e, inconspicuously 1.5-2.5 em. high, .25-
t~risted,
.75 mm. cliam.; uuilocular sporangia broadly elliptical, -±0-45,u long,
30-35,u wide; otherwise as the species.
GrmYing on rocks, usually in shf:'ltered localitie at high tide
lc.~vPl
or even above, where the spray da ·J1 es. Common on the central 1ali
forilla coast, and known as far north as Coos Bay, Oregon. The type
locality is F ort P oint, San Francisco, California.
rrhis form from the species chiefly in size and in habitat.
differ.~
When the coast between Coos Ba)' and Pngrt i. more thor
~onnd
oughly investigated forma t rnuis will doubtle:s he found growing
lower and lower down in the littoral belt a " rell as becoming larger
and larger northward , merging into the Puget ound form.
386 ·c niversity of Californz:a Pttbliaati:ons in Botany (VoL. 6
Pelvetia fastigiata f. gracilis Setchell et Gardner forma nov.
Profuse dichotomo-ramosa; ramis centralibus longioribus, externis
curtioribus, plant am totam plus minusve sphericam efficientibus;
ramellis curtis densisque ad basem frequenter orientibus; frondibus
gracilibus, ramis terminalibus 1- 3 mm. diam.
Plants profusely dichotomously branched, central branches becom
ing much longer than those on the outside of the mass, giving to the
whole plant a m01·e or less spherical outline; frequently branches arise
from near the base and develop a mass of short branchlets ; fronds
slender, the terminal branchlets 1-3 mm. diam.; fruiting in the sum
mer and autumn.
Growing in the middle of the littoral belt. Carmel Bay, Pacific
Grove and Santa Catalina Island, California. In these localities
plants grow in groups quite separate from the typical P. fastigiata .
The type locality is Carmel Bay, California.
This form, though morphologically connected with the species by
plants intermediate in size, seems to be sufficiently distinct to warrant
a form name on account of its profuse and delicate branches, and
different fruiting season. Plants of forma gracilis begin fruiting
early in the summer and r each their climax in the late fall, whereas
those of P. fastigiata r each their maturity two or three months later.
Sargassum dissectifolium Setchell et Gardner sp. nov.
Sargassum, p·il'Ltlifentrn (Turn .) Ag., F arlow, Anderson and Eaton,
Alg. Exsicc. Amer .-Bor., no. 102; Collins, Holden and Setchell, Phyc.
Bor.-Am. (Exsicc.), no. 537 a, not b. Not C. Ag., Sp. Alg., 1823, p.
27. Not Yendo, Fucaceae Japan, 1907, p. 54. Not F1wus pil'Ltlif e-r
Turn ., I-Iist. Fus., vol. I, 1808, p. 145, pl. 65.
P er enne, dioicum; radice salida, rugosa, plus minusve discoidea;
stipite tereti, usque ad 18 em. longa, apice 2-5 ramos teretes alter
n osque post fru ctificationem dissolutos fcrentibus; ramis primariis
ramellos steriles (folia ), alternos, frequenter dense congestos, den
droidc et dichotomo in 15-25 segmentis parce complanatis, 2-3 em.
longis, costatis, dissectos, gerentibus; ramis vetustis oribus projectis
curtis spinosis plus minusve ramosis inclutis; ramis secondariis
numerosis ex axillis superne curtioribus, inferne longioribuR ori
entibus, folia depauperata eornrn frondium principalium similia
gerentibus vesiculas et receptacula in axillis producentibus ; vesiculis
vuJgo solitariis, levibus sphaericis, 3.5-6 mm. diam., in apicibus
peclicellorum diametron vesiculorum aequantorum ; r eceptaculis in
axillis segmentorum stirilium dense dendroide congestis, multo vesi
cula aut folio depauperate ornatis; frondibus fructiferis saepe nudis,
foliis disintegrantibus; conceptaculis conspicuis; cryptostomatibus
.
nnmeros1s.
Frond arising from a solid, rugose, more or less disk-shaped hold
fast, 4.5- 7 dm. high; stipe t erete, up to 18 em. long, bearing 2- 5
tcrete, alternate branches at its summit, distintegrating after fruiting;