Pes “OED OG ONTACE AE 23 
- Oedogonium and Bulbochaete grow in small permanent bodies 
of water rather than in lakes. The order of importance of algal 
habitats in this region of the United States for these two genera 
is: permanent ponds, lakes, temporary ponds, streams, and 
stream oxbows. Nearly 80% of the fruiting records for Oedo- 
gonium come from forms collected in the permanent ponds and 
the lakes. Streams are relatively poor habitats for fruiting 
species in spite of the prominent holdfast cells of the filaments. 
(See Table ITT). 
TABLE III. 
Data showing relative importance of Oedogonium habitats in the 
North Central States. 

HABITAT NUMBER OF PERCENTAGE 
RECORDS 
PRICE ONGS: sactee yi. kee ts oes. ke eS | 603 54% 
FEO Se cal oct aia oT iotes Ate Eee tine eae 254 23% 
MemmacetauerOnds: 5.2224 oes feiss ca eae oe 172 15% 
SURBATTS Sa ole Seo eR OU 0 Sibatn Scrree ates a ceaae 65 6% 
Simeaian ON en SESE ee 6 nas io aio eee ame 20 2% 
RSE ee eshte ne ere Aa OVS 1114 100% 
The above table gives the relative importance of Oedogonium 
habitats in the North Central States for the 1114 records. 
Nearly 100 records for the genus Bulbochaete show a very similar 
distribution among habitats in the same region. 
_ Periodicity as applied to Oedogonium and Bulbochaete has 
been studied by Fritsch and Rich (1913), Hodgetts (1921), 
and Tiffany and Transeau (1927). It has been shown that the 
species of these genera produce reproductive structures at rather 
definite seasons of the year. The particular months of maximal 
sexual reproduction vary with the species, the geographical 
location, and the length of the growing season. The smaller 
forms as a rule have a short vegetative phase and fruit early in 
the growing season; the larger forms have usually a longer 
vegetative period and fruit later in the growing season. In 
north central United States maximal sexual reproduction is 
reached in May and in July (see text fig. 1) both in the annuals 
and perennials. Many species reach a second maximum in 
October, which is doubtless the development of a second 
generation. 
