11 Feb.. 1918.] .-1 Water Weed at Toorourrong. 109 



CrimL.on Bottlebrusli {Callistevion Ia7tceolatvH) Tlwj leaves are, how- 

 ever, usually more pointed, and the flowers generally smaller, than in 

 the Crimson Bottlebrush. 



It is found in all parts of Victoria, particularly along the Yarra, 

 Ovens, Goulburn, and other rivers. It is a nectar and pollen producer 

 like the other species. 



The Swamp Bottlebrush {Gdllistemon paltidosus). 

 A species with narrow, almost linear, leaves, growing in swampy 

 localities. No data as to itft honey or pollen yielding qualities are so 

 far available. 



The Mountain Bottlebrush (Callistemon Sieberi). 

 This is a mountain species with short, almost linear, leaver, from 

 ^ to I of an inch in length, and red flowers, usually in short spikes.. 



The Pine Bottlebrush {Callistemon jyithyoides). 

 A tall shrub confined to the north-east of the State. The leaves are 

 linear, more or less:, distinctly channelled on the upper side, rigid, blunt, 

 or sharply pointed, from 2 to 4 inches long, resembling pine leaves, 

 hence the name. The flowers are rather large and of a dull yellowish 

 green, including the anthers. 



The Narrow-leaved Bottlebrush (Callistemon linearis). 

 Ufrually a tall shrub with narrow linear leaves, from 2 to 5 inches 

 long, blunt or sharp-pointed. The flowers are large, with stamens about 



1 inch long, dark or pale red, sometimes greenish 



The Prickly Bottlebrush (Callistemon hrachyandrus). 



The Prickly Bottlebrush it' a tall, stiff, bushy shrub or small tree, the 



young shoots softly hairy. The leaves are linear, channelled above, 



rigid, and sharply pointed, and from | to 1^ inches in length. The 



flower spikes are loose and interrupted, or sometimes dense, and rarely 



2 inches in length. This species is found in the Murray Desert. 



A WATER WEED AT TOOROURRONG. 



By Alfred J. Ewart, D.Sc, Ph.D. 



(Government Botanist of Victoria, and Professor of Botany and Plant 

 Physiology in the University of Melbourne). 



The Metropolitan Board of Works makes use of an artificially con- 

 structed lake at Toorourrong for settling the water derived from the 

 Plenty Ranges and "Wallaby Creek system. Such a lake is bound, in 

 course of time, if it fulfils its function, to silt up slowly, and thus become 

 liable to be choked by water weeds. 



The weed Vallisneria spiralis was present at one point in the lake 

 for many years without spreading, but suddenly in one season extended 

 over a much larger area, so that the problem of either suppressing it or 

 keeping it within bounds became of importance. This weed has spread 

 over large areas of Europe, Asia, America, Africa, and Australia. It 

 grows in stagnant, or slowly-flowing water, chiefly where there is a 

 muddy bottom, and, if too abundant, might have a tendency to affect 

 the quality of the water in autumn owing to the presence of large 

 numbers of its decaying leaves. 



