Pleurococcus marinus Collins

• Region

  North America

• Country

  United States of America

• State/Province

  Maine

• County/Municipio

  Cumberland Co.

• City/Township

  Harpswell

• Locality

  Stover's Point, in a marsh pool

• Coordinates

  43.7579, -69.9981

• Coordinate Uncertainty (m)

  318.569

• Georeferencing Method

  Georeferencing Quick Reference Guide, Version 2012. Located coordinates of geogr. center of Stover's Point. Measured from coord. to farthest extent of the point to find linear extent (307 m). Input info. into MaNIS Georef. Calc. to find uncert. rad. (Bounded Area).

• Geodetic Datum

  WGS84

• Distribution

  Map all specimens of this taxon

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Pleurococcus marinus Collins, n. sp.
Khodora 9:197. pi. ?6. 0 1907.

Cellulis sphaericis, 10-40 ji diam. cum membrana cellular!;
membrana 2 crassa; colore variants ab auriantiaco intenso
ad viridem chlorophyllaceam veram; Reproductione per aplano-
sporas divisione repitita formatas, 8-64 in cellula; membrana
cellular! distincta et admodum crassa dum in cellula matricali;
congerie sporarum substantia gelatinosa inclusa.post solutionem
cellulae matricalis formam sphaericam diu servante.

Cells spherical, 10-40 p. diam., including cell wall; wall
about 2 11 thick; color from deep orange to true chlorophyll
green. Reproduction by aplanospores, formed by repeated divi-
sion, 8-64 in a cell, spore wall distinct and relatively thick
while still in the mother cell; mass of spores retaining the sp-
herical form and held in a gelatinous mass long after the disap-
pearance of the mother cell wall.

This plant was distributed through a mass of floating algae
in shallow pools in a salt marsh at Stover?s Point, Harpswell,

Maine, July, 1906. It formed so large a proportion of the mass as
to give a brick- or orange-red color to the whole, the other spec-
ies being Lyngbya aestuarii (Mert.) Liebm. Cladophora expansa>Kiitz.
and other forms usually found in such localities. It has been dis-
tributed as No. 1316 of the Fhycotheca Boreali-Americana. The gen-
us Palmellococcus-was founded by Chodat in 1894 J for the single
species P . minlatus (Protococcus miniatus Kiitz., Pleurococcus mini*
atus Nag.), which is not uncommon on walls and windows of green-
houses, bat whose native habitat is unknown; Chodat reports its re-
production under ordinary circumstances, to be by bipartition, rare-
ly quadri-partition of the cell; but in culture in pure spring wat-
er the contents of a cell is by repeated division sometimes trans-
formed into 16, 32 or 64 spores with delicate membrane, escaping in
a mass with a gelatinous envelope. This latter form of reproduct-
ion is the only one observed in P. marinus.but practically all of
the Harpswell material seemed toHse in some stage of this process.
The color of the cell ranges from deep orange to pure green; the
largest cells were green, but cells of this color were found of all
sizes down to the smallest. The only distinction other than color
was that the largest green cells had a thinner wall than the small
or moderate sized cells, either green or orange, and that the color -
ed cells seemed more active in spore formation. The wall of the
spore was fully developed while the wall of the mother cell was
still perfect; after the disappearance of the latter the spores re-
mained in a spherical gelatinous mass for a long time, until they
had increased very materially in size; colonies of 32 cells were
observed, retaining the spherical form with a diameter of 100 u.

Some of the plant^was kept alive for several weeks, but not under
the normal conditions of a salt marsh pool; in this material were
finally found numerous spherical colonies, in which the contents of
each cell had divided into aplanospores of a second generation, much
smaller than any noticed in the normal condition of the plant.

From P. miniatus, marinus is distinguished by the larger
cells, those of ¨0 miniatus being 3-15 U diam.;by the thicker
walls of the aplanospores, and by the totally different hab-
itat. According to the figures of P. miniatus in Chodat?s
Algues Vertes de la Suisse, fig. 80, the gelatinous vesicle
of the spores is less regular in form in that species and less
persistent.

1 Chodat, Mat‚riaux pour servir h l?histoire des Protococ-
co‹d‚es. Bull. Herb. Boissier, Vol, II, p. 429, 599.

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July 16, 1906,

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