NEW SPECIES OF GREEN ALGAE 
299 
diam. oogonia 
diam. oospores 
diam. androsporangial cells 
48-60 )u, length 62- 74 ju; 
46-58 fx, length 60- 72 n; 
20-24 length 18- 22 n. 
This species is closely related to Oe. obtruncatum Wittr. It differs 
in being idioandrosporous, having generally larger dimensions, and in 
the form of the terminal cell. It has been found in Hodgen's pond, and 
the East Big Four pond, Charleston, Illinois. Fruits in summer and 
autumn. Type in herb. E. N. T. Collections No. 1967, and 1963. 
Plate XXIX, figures 1-5. 
Oedogonium illinoiense nov. sp. 
Oedogonium dioicum, nannandrium, gynandrosporum ; oogoniis 
singulis, subglobosis vel oboviformi-globosis, poro mediano apertis; 
oosporis globosis vel subglobosis, oogonia fere complentibus, membrana 
duplici; episporio costis spiraliter dispositis, costis spiralibus numero 
4-7, utrinque in polo, in sectione horizontali, fere mediano, nunquam 
verticali sito conniventibus, endosporio laevi; cellulis suffultoriis 
tumidis; androsporangiis 1-5-cellularibus; cellula fili basali forma, ut 
vulgo, elongata; nannandribus palululum curvatis, in cellulis sufful- 
toriis sedentibus, antheridio exteriore, 1-4-cellulari; 
crassit. cell, veget 13-18 fx, altit. 76-129 n; 
crassit. cell suffult 32-40/1, altit. 50- 73 m; 
crassit. oogon 51-60 /z, altit. 60- 70 /t; 
crassit. oospor 45-56/1, altit. 48- 66 /x; 
crassit. cell, androsp 13-17 /i, altit. 17-22/1; 
crassit. stip. nannandr 14-17/1, altit. 37- 57 /t; 
crassit. cell, antherid 9-12 /t, altit. 15- 23 /t. 
Dioecious, nannandrous, gynandrosporous ; oogonia sugblobose to 
oboviform-globose, occurring singly in the filaments; pore median; 
oospores globose or subglobose, nearly filling the oogonia, membrane 
double; the outer spore wall marked by 4-7 spiral ribs uniting at the 
poles, the polar axis always placed in a transverse position, never 
parallel with the filament, the inner spore wall smooth ; suffultory cells 
swollen; androsporangia 1-5-celled; basal cell of the filament elon- 
gated; dwarf males slightly curved resting on the suffultory cell, 
antheridium exterior, 1-4-celled; 
diam. vegetative cells 13-18 /i, length 76-120 /i; 
diam. suffultory cells 32-40 /i, length 50- 73/1; 
diam. oogonia 51-60 /t, length 60- 70 /i; 
diam. oospores 45-56/1, length 48- 66 /x; 
diam. androsporangia 13-17 /i, length 17- 22 /t; 
diam. dwarf male stipe 14-17 M. length 37- 57 /i; 
diam. antheridia 9-12 /t, length 15- 23 /c. 
