microns in length. The cells are 2 by 4 mi- 1915. (Verhandl. Naturhist.-med. Verein z. crons and possess several small false vacu- Heidelberg, N.F. 13, 1915, 408.) oles which are sharply but irregularly out- spi.ra'le. Gr. noun spira a spiral; M.L. lined. The cytoplasm of the cells emits a adj. spiralis spiral. marked bluish gleam of light. Spirally twisted trichomes, 1.0 to 1.5 by Source: From pools and shallow lakes 40 to 160 microns, with a wave length of 8 which contained an abundance of decom- to 14 microns. The cells contain numerous, posing algae. small but long false vacuoles. Habitat: Found in fresh water. Source: From a pool in Germany rich in Chara.
4. Pelonema (?) spirale Lauterborn, Habitat: Found in fresh water.
FAMILY III. CRENOTRICHACEAE HANSGIRG, 1888.
(Oesterr. bot. Ztschr., 36, 1888, 228.)
Cre.no.tri.cha'ce.ae. M.L. fem.n. Crenothrix type genus of the family; -aceae ending to denote a family; M.L. fem.pl.n. Crenotrichaceae the Crenothrix family.
Trichomes attached to a firm substrate and show differentiation of base and tip. Unbranched or show false branching. Sheaths may be thin, delicate and not encrusted with oxides of iron or manganese, or they may be plainlj^ visible, thin and colorless at the tip and thick and encrusted with iron or manganese oxides at the base. Cells disc-shaped to cylindrical, dividing to produce spherical, non-motile conidia. Individual cells may also slip out of the sheath to grow into new trichomes. Found in fresh and salt waters.
Key to the genera of family Crenotrichaceae.
I. Attached trichomes which are swollen at the free end.
- A. Sheath thick, storing iron or manganese oxides.
Genus I. Crenothrix, p. 272.
- B. Sheath very delicate, always colorless.
Genus II. Phragmidiothrix, p. 273.
II. Attached trichomes which are tapered at the free end.
Genus III. Clonothrix, p. 274.
Genus I. Crenothrix Cohn, 1870.
(Beitr. z. Biol. d. Pflanz., 1, Heft 1, 1870, 108.)
Cre'no.thrix. Gr. noun crenus a fountain, spring; Gr. noun thrix, trichis a hair; M.L. fem.n. Crenothrix fountain hair.
Trichomes attached to a firm substrate and swollen at the free end. Unbranched or show false branching. The sheaths surrounding the trichomes are plainly visible, thin and colorless at the tip and encrusted with iron or manganese o.xides at the base. Cells disc-shaped to cylindrical, dividing to produce spherical, non-motile conidia of two types: micro- and macroconidia. Individual cells may also slip out of the sheath and form new trichomes. Found in stagnant and running waters which contain organic matter and iron salts.
The type species is Crenothrix polyspora Cohn.
1. Crenothrix polyspora Cohn, 1870. noun spon/s a seed; M.L. noun spora a spore; (Beitr. z. Biol. d. Pflanz., 1, Heft 1, 1870, M.L. adj. polysporus many-spored. 108.) Trichomes long (up to 1 cm), articulated, po.ly'spo.ra. Gr. adj. poly many; Gr. unbranched and sessile. There is consider-
