448 
The Ohio Naturalist. 
[Vol. IX, No. 4, 
10. Conjugatae. 1200 species. 
Unicellular or filamentous, unbranched, unattached, green, 
mostly freshwater algae, with a single nucleus and with one or 
more highly specialized chloroplasts with pyrenoids in the cells; 
reproduction by division and by zygospores formed by the con¬ 
jugation of two similar or nearly similar cells, often joined by the 
development of a special conjugation tube. 
11. Siphoneae. 625 species. 
Coenocytic terrestrial or aquatic green algae usually filamen¬ 
tous, more or less branched, and with or without transverse 
septa; reproduction by zoospores, by ciliated gametes, or by true 
sperms and eggs. 
12. Conferveae. 600 species. 
Simple or branched filamentous green algae, sometimes hav¬ 
ing the cells in discs or sheets, usually attached, having normal 
cells with one nucleus; reproduction by means of zoospores and 
by motile gametes or by heterogametes, the egg being stationery; 
commonly with a primitive alternation of generations; chloro¬ 
plasts one or more, usually with pyrenoids. 
Subclasses, Isogamae. 
Heterogcimae. 
13. Phaeosporeae. 385 species. 
Normally brown-colored marine algae ranging from rather 
simple filamentous forms to very large, highly developed organ¬ 
isms with a distinct conducting tissue whose cells contain sieve 
plates; usually attached, the frond often differentiated into stem 
and leaf-like structures; reproduction by zoospores produced in 
unilocular sporangia, and motile gametes produced in pluri- 
locular sporangia; both types of sporangia exposed. 
14. Cyclosporeae. 316 Species. 
Medium to large, marine, brown algae, attached, branched, 
and usually flattish; reproduction by small biciliate sperms and 
large non-ciliated eggs which are discharged and fertilized in the 
water; reproductive organs sunken in conceptacles. 
15. Dictyoteae. 82 species. 
Erect, attached, marine, brown algae with flat leaf-like fronds; 
nonsexual reproduction by nonmotile tetraspores; sexual repro¬ 
duction by means of non-ciliated eggs produced singly and 
finally discharged from the oogonium, and sperms with one flagel¬ 
lum produced in many-celled antheridia. 
16. Bangieae. 46 species. 
Marine or freshwater red or purple algae with filamentous 
or thalloid fronds; reproduction by single thallus cells and by the 
production of antheridia and oogonia from ordinary thallus cells, 
the antheridium developing nonciliated sperms, the oogonium 
which is without a distinct trichogyne usually developing a single 
stationary egg. 
