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We have alkali, of course, in connection with our bore waters. An artesian bore 
is sunk, the water is more or less used for drinking purposes by stock, and the rest escapes 
to impregnate the surrounding soil. In some cases it destroys the few trees in the 
vicinity and, in order to re-establish tree-growth, careful experiments require to be mado 
in regard to trees known to be saline -tolerant. 
(b) Sand encroachment. 
This is dealt with to some extent in Part LVII. of the present work, under the title 
" The Sand-drift problem in New South Wales." 
IV. Parasites. 
(a) True Parasites (Mistletoe, &c.). 
(b) Hemi-Epiphytes (Strangling Figs). 
(c) Fungi. 
(d) Weeds. 
(a) Parasites (Mistletoe). The word parasite is from the Greek, and was applied 
by the ancients to persons who intruded, uninvited, into the houses of the rich in order 
to obtain a free meal. The term is in strictness applied to plants which develop suckers 
or haustoria, which are the roots which feed on the parent plant. The word " haustoria " 
is from the Latin, haustor, a drawer, like the circular leathern suckers that boys amuse 
themselves with. 
According as the parasites affect the stems or roots of plants we have two principal 
divisions : 
(1) Stem parasites, including Mistletoes These consist of plants with more or 
less succulent leaves which are pendent from the branches of trees, and frequently 
simulate the foliage of their hosts. The Mistletoes include about 500 species belonging 
to the family Loranthacese, also about twelve species belonging to the genus Henslowia, 
Family Santalacese. 
(2) Root parasites. A few plants are root-parasites that is to say they arc 
parasitic on the roots of their hosts. They are much less known than the former. 
That Santalum is a root parasitic was established in 1871 by John Scott, Curator 
of the Royal Botanic Gardens, Calcutta. The haustoria of this genus show a structure 
in all essential points identical with that of the haustoria of Thesium (another Australian 
genus). Santalum, of course, produces the sandalwood of commerce, and the above 
discovery is doubtless the key to its cultivation. 
Our Native Cherry (Exocarpus) and the Quandong (Fusanus) also belonging to 
the Santalaceae, are also parasitic on the roots of others, and this probably explains 
the difficulty that always attends the cultivation of these trees. As regards Santalum 
album, it has been proved to be parasitic on Palms, two large Graminese (Saccharum 
tmd Bambusa) and certain Araliacese ; and Mr. C. A. Barber has recently added Lantana 
and Casuarina. 
