Page:Bergey's manual of determinative bacteriology.djvu/292

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270
ORDER II. CHLAMYDOBACTERIALES

length; including the sheath, they measure 1.5 to 1.7 microns in diameter. Several tri- chomes arising from the same point and each trichome developing a few false branches produces a fan-shaped appearance. All trichomes end at approximately the same distance from the starting point. The trichomes are bent so that the entire fan- shaped group arches somewhat. The indi- vidual cells are rod-shaped, 0.5 by 3.0 mi- crons. Iron oxide is deposited in the sheath. Around this, a gelatinous mass is formed, as much as 22 microns in length and ovoid in form. Iron is not deposited in this gelatinous mass. Source: Found on slides submerged in an aquarium in Berlin in which Cahomba was growing. Habitat : Found in fresh water.

FAMIILY II. PELOPLOCACEAE BEGER, Fam. Nov.

Pe.lo.plo.ca'ce.ae. M.L. fem.n. Peloploca tj-pe genus of the family; -aceae ending to de- note a family; M.L. fem.pl.n. Peloplocaceae the Peloploca family.

Long, unbranched trichomes usually enclosed in a thin, delicate sheath. Cells within the trichomes, when in the living state, contain false vacuoles which are easily discerned by a reddish gleam of light which they emit; the cytoplasm of the cell appears bluish white. Gen- erally non-motile, but motile species may occur. Reproduction is by transverse fission of the cells. Unattached forms found in fresh-water ponds with decomposing algae.

Key to the genera of family Peloplocaceae.

I. Trichomes lie parallel to each other in bundles or bands.

Genus I. Peloploca, p. 270.

II. Trichomes occur singh

Genus II. Pelonema, p. 271.

Genus I. Peloploca Lauterborn, 1913.

(Allgem. bot. Ztschr., 19, 1913, 99.)

Pe.lo'plo.ca. Gr. adj. pellos or pelos dark-colored; Gr. noun place a twining, a braid or a twist; M.L. fem.n. Peloploca dark-colored braid or twist.

Trichomes of cylindrical, colorless cells with no evident sheath. Occur as motionless bundles or bands. Cells contain false vacuoles which emit a reddish gleam of light. Non- motile. Occur in fresh-water ponds where Char a sp. is undergoing decomposition. Frequently overlooked because the trichomes resemble plant fibers.

The type species is Peloploca undulata Lauterborn.

1. Peloploca undulata Lauterborn, 1913. (Allgem. bot. Ztschr., 19, 1913, 99.) un.du.la'ta. L. adj. undulatus undulated, with waves. Cells 6 to 10 microns long. The trichomes are spirally twisted into wavy bundles that are tightly wound together. The bundles reach a length of 60 to 150 microns. Non- motile. Source : Found in Germany in ponds where Chara sp. was growing. Habitat: Presumably widelj' distributed in fresh-water ponds.

2. Peloploca taeniata Lauterborn, 1913. (Allgem. bot. Ztschr., 19, 1913, 99.) tae.ni.a'ta. L. adj. taeniatus band-like. Cells 3.0 to 4.0 microns long. Trichomes united into rather broad, frequently twisted bands. These may have the appearance of a grating or lattice because of the presence of pseudo vacuoles in the individual cells.