210 A CONTBIBTTTION TO, ETC. 



readily in peat and loam, and may be increased like other herba- 

 ceous vegetables. Damasonium ovalifolium (our Water Lily), 

 Vallisneria spiralis, Villarsia geminata, and Azolla pinnata, are all 

 aquatic plants, and available for garden ponds. 



In concluding my review of the ornamental plants of the 

 Parramatta district, I cannot but express regret that many of 

 them are so little appreciated by horticulturists. If we had, in the 

 neighbourhood of the town, a garden for the exclusive purpose of 

 raising native plants, and of arranging them systematically for 

 the instruction of persons desirous of studying Australian Botany, 

 the beauty of our Flora would be seen and acknowledged, and a 

 great step would be taken towards the development of our re- 

 sources. In the first place, the cultivation of the varieties of 

 Eucalyptus a genus which has hitherto been so perplexing to 

 men of science might lead to an accurate arrangement of the 

 species, and to the knowledge of the variations of which they are 

 susceptible ; whilst a careful investigation might render it evident 

 whether any of the species are exposed to hybridization. I am 

 aware that Dr. E. Mueller is of opinion that this process scarcely 

 extends to the genus, because fecundation of the germen takes 

 place whilst the calyx of the flower is yet closed by the oper- 

 culum ; but when we see the numerous varieties of Grey Gum 

 or Bastard Box, all of which must be referred to the same species, 

 and hear the expressions of practical men on that subject, it 

 seems probable that something of the kind may be effected by 

 the labours of insects, and that by boring through the operculum, 

 and conveying the pollen of one tree to the stigma of another, 

 they may occasion some of the anomalies which we witness 

 around us. A systematic arrangement of our medicinal plants 

 aVo, is highly desirable, as a means of encouraging Medical 

 Botany, and of assisting the student in his researches into the 

 nature and properties of those species, which are likely to prove 

 efficacious in healing the diseases of the human constitution. 

 Such an investigation is eminently calculated to improve the 

 minds of young men entering on the medical profession, and to 

 obviate the necessity of sending to foreign countries for remedies 

 which could be procured here in all their native freshness. As 

 regards plants and trees, also, which are supposed to afford fruit 

 or roots capable of being prepared for food, a systematic garden 



