OEDOCLADIUM 51 
Genus II. Oecedocladium Stahl. 
1891, p. 339; Hirn 1900, p. 374; Collins 1918, p. 71; Lewis 1930. 
Terrestrial or aquatic, branching, rhizoidal; if terrestrial, partly 
subterranean and subhyaline, partly above ground and green; vegetative 
cell cylindrical or nearly so, growth chiefly by division of terminal cell 
of a filament or branch; asexual reproduction by “‘akinete”’ and zoospore; 
oogonium arising by a simple division of a vegetative cell; sexual 
reproduction both monoecious and dioecious, nannandrous. 
KEY TO THE SPECIES OF OEDOCLADIUM. 
0 OLE SEVGIES. 6 SESS e 2 ee ee Pe 
PUNOCHOUS nannandrous, aAguatiCunse settles ancient es -~? 4. O. hazenii 
SSE PENTA) AG PR ee ia a ge RS ee ee a 3 
Le QUEST PGS) SS VRS DS a Se ei ak ee 4 
SME RECAUIVCNCElLE/ ZUM eee <5 re cle aus, fe si olen) | EELS + pda aeada ee 1. O. protonema 
3. Vegetative cell 12-18 X56-78u.................. oa RY ee Le 3. O. media 
FRO OLOMMIM OS OOM rane ciclo eho ethos es oye. ede. 3. O. media 
PO) SOIT FU COOL I aerate cidiass t's Sees arcis ss Lee 2. O. albemarlensis 
1. O. protonema Stahl. 
(Pl. LXIII, figs. 619-623.) 
1891, p. 347, Pl. XVI, figs. 1-6, Pl. XVII, figs. 1-12; Hirn 1900, p. 374, Pl. 
LXIV, fig. 396. 
Monoecious; oogonium single, subglobose, rarely terminal, pore 
median; oospore globose, filling oogonium, spore wall smooth; anther- 
idium scattered, 1-6; vegetative cell 7X20u, rhizoidal 3X (up to)300u; 
oogonium 50-76 X 58-76; oospore 45-60 X 45-60y. 
Germany (Strassburg). 
2. O. albemarlensis Lewis. 
(Pl. LXIII, figs. 613-617.) 
In Collins (as O. albemarlense Lewis) 1918, p. 71, Pl. III, figs. 22a and 22b. 
Monoecious; oogonium single, mostly terminal, subglobose with 
conical apex (if terminal), pore inferior; oospore globose, not filling 
oogonium, spore wall of three layers: outer layer smooth, middle layer 
angulate (in optical section undulate), inner layer smooth; antheridium 
to 9; vegetative cell subcylindrical; terminal cell with conical apex; 
vegetative cell 25-40 X50-150y, rhizoidal 4-10 X (up to)350u; oogonium 
90 X95; oospore 69 X 69u; antheridium 20-25 X 8-19; zoospore 32-50y. 
United States: Virginia (on sandy loam, bank of the 
Rivanna, near Charlottesville, Albemarle County) growing with 
Vaucheria and Riccia. Collected by Professor I. F. Lewis. 
