ï~~2003
THE MICHIGAN BOTANIST
149
A NEW SPECIES OF CHAETONEMA (CHLOROPHYCEAE)
Daniel E. Wujek Rufus H. Thompson1
Department of Biology Department of Botany
Central Michigan University University of Kansas
Mt. Pleasant, Michigan 48859 Lawrence, Kansas 66045
[email protected]
ABSTRACT
A description of a new species of the green algal genus Chaetonema, C. minima, is presented. A
key to the species of Chaetonema now recognized is given.
INTRODUCTION
Chaetonema Nowakowski (1877), a green alga placed in either the
Chaetophoraceae (Smith 1950) or Aphanochaetaceae (Bourrelly 1966), grows
epiphytically on other algae, especially those which produce large amounts of
mucilage, e.g., Batrachospermum, Chaetophora, Tetraspora. It is because of the
mucilage of its "host" that this genus is often overlooked. The thallus consists of
irregularly twisted main branches which bear short lateral branches terminating
in long hyaline unicellular setae. In addition to the type species, C. irregulare,
one other species has been described, C. ornatum (Transeau 1943).
In North America, C. ornatum has been observed from Alabama and Nova
Scotia (Transeau 1943), while C. irregulare has been reported from the New
England area (Collins 1918; Prescott & Croasdale 1942) and Michigan and Wisconsin (Prescott 1962).
This paper reports the description of a new species of Chaetonema observed
initially in several northern Minnesota locations, and subsequently observed
from various Michigan sites.
METHODS AND MATERIALS
Samples containing Chaetonema minima were collected from the following sites: Michigan:
Charlevoix County-Greene's Lake, July 1990-94, Montcalm County-Vestaburg Bog, June to
July-sporadically 1970-95; and in Minnesota: Becker, Clearwater, and Hubbard County lakes and
ponds in the Itasca State Park and adjoining waters, June-July 1960, 1964-1965 (waters described in
Meyer & Brook 1968).
Observations were made from both freshly collected material and from stock cultures grown in
1Deceased 3 June 1980. Dr. Thompson is included as an author as he first directed my attention
to this organism in 1964 when he was teaching a freshwater algae course at the University of Minnesota's Biological Station and I was his teaching assistant and graduate student. He was the source
for some of the descriptive data included in this paper. I 'rediscovered' the organism many years later
in Michigan. He had never taken the time to formally describe the organism as new to science.
