194 
III. STEPHANOKONTA E. 
OEDOGONIACEA E. 
Oedogonium, Link, 1820. 
0. Vaucherii (Le Clerc), Braun Chytr., 381, t. 2, f. 13. In the 
temperate house pools; with oogonia in À pril, 1902 ; disappeared 
in May, 1902. 
0. capillare (Linn.), Kütz. Phyc. Gen. 225, t. 12, f. 1-10. 
Growing on Nitella syncarpa, contained in a glass ves sel in one 
of the pits, April, 1902. This species is cnrious in that the apical 
cell of each filament is provided with a tip, which is formed 
before or at the same time as the root on the developing zoospore. 
During the summer months this species has been slowly dying ; 
it is now practically colourless, the cells being crowded with 
starch granules (cp. Annals of Botany, vol. xvi., 1902, 481). 
0. caleareum, Cleve in Wittr. Disp. Oedo 0g -, 135. In the warm 
tanks of the water-lily house, with oogonia, April, 1902 ; also in 
Victoria Regia tank (ep. Cooke, Brit. Freshw. Algae, 165). This 
ecie 
earbonate of lime, giving its cells a rugged, black, granular 
appearance. M e qum 1902. 
O. cardiacum (Hass.), Wittr. loc. cit, 135. Growing on th 
leaves of Vallisneria rans: in the middle tank of the water-lily 
house, 1902. Only oogonia and oospores were observed. 
0. stagnale, Kiitz. Spec. Alg., 368. Tank in Herb. Dptmt., 
June-September, 1902. Antheridia and young oospores observed. 
As far as I am aware this species has not yet been found in this 
country. 
. Sp. With a water-moss from the river Severn in a glass 
vessel in the Herb. Dptmt., 1902. This species has remained sterile 
ever since I first observed it in April. Diam. of filaments = 4-5y ; 
cells about 4—5 times as long. 
IV. CONJUGATAE (AKONTAE). 
1. MESOCARPACEAE. 
Mesocarpus, Hass., 1845. 
Hass. Freshw. Algae, 166. Together with 
M. parvulus, 
Ulothriz in tank of one of the pits, A il 1902. Z t 
observed. pits, April, 1202. Zygospores no 
M. pleurocarpus, De Bary Conj., 81, t. ii. fig. 14. Formiug 
large yellowish-green floating masses in the lake, Apzil-Bepiember, 
1902 ; laboratery tank, 1902.  Zygospores not observed. 
