June.j Excursion to Lake Corangamite and District. 29 



2. — The Lakes. — Aquatic botany is better studied earlier 

 in the year than Easter, but only folk of a leisured class can 

 fit their excursions always to appropriate seasons. In respect 

 of material to be gathered, the zoologists were more fortunate 

 than the botanists in the excursion from a seasonal point of 

 view. The lake flora was collected from several places, and has 

 not been exhaustively examined, yet enough has been gathered 

 and specifically determined to give a good idea of the algo- 

 logical condition of the two lakes at the date of our visit, so 

 that the outstanding features of the lakes Colac and Coran- 

 gamite may be stated as follows : — 



Lake Colac. — Fresh or slightly brackish water, containing a 

 floral plankton and a few attached species. No visible water- 

 weeds, excepting a solitary plant of the introduced dock, 

 Rumex, sp. 



(a) Plankton consisting almost exclusively of Botryococcus 

 Braunii, but with an occasional Closterium cynthea, and with 

 a few species of diatoms present. 



(b) Attached Algse. — The only conspicuous growth was 

 Cladophora flavescens, which was attached to jetties, posts, 

 unused boats, &c, and to the aforesaid dock. The Cladophora 

 bore sparingly sterile filaments of a species of (Edogonium, 

 and less of Bulbochaeta, and also Hydrianam heteromorphum 

 and Chamceosiphon incrnstans, the latter being seen occasion- 

 ally also on Copepoda. Oscillatoria, sp., was associated with 

 the Cladophora, but only isolated filaments were found. The 

 smooth mud bottom of the lake was barren. 



Lake Corangamite. — This is a salt lake with a marine 

 atmosphere — the large expanse of salt water, the rock-bound 

 coast with shelly beaches, and littoral ulvaceous fringe of 

 characteristically smelling " seaweed " contrasting well with 

 the smaller, less exposed, and fresh-water Colac ; more so when, 

 as at irregular periods, such weeds as Heleocharis sphacelata, 

 Triglochin procera, &c, make their appearance in the latter. 



(a) Plankton plants absent. 



(b) The littoral alga flora consisted almost exclusively of 

 Enter omorpha Ralfsii, Harv., and this almost encircled the 

 lake with a high level mark of dry and white bleached felt, 

 which covered the basaltic rocks and rendered walking on 

 them with bare feet a matter of comfort. At the water's edge, 

 and for a considerable distance " seawards " along the gently 

 sloping bottom, this weed formed flocculent masses, sometimes 

 waving upwards from the rock base, or floating in large gas- 

 borne masses that made wading difficult. The only associated 

 alga was Oscillatoria (littoralis ?), in isolated filaments. 



(c) Shore Macrophytes and Alga?. — On the western side of 



